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ABS Adult Literacy and Lifeskills Survey (ALLS) - 2006 In this paper, the functional definition of literacy and numeracy is used. That definition is consistent with the human capital approach to literacy and numeracy. Functional measures of literacy and numeracy give a more sophisticated view of people’s abilities than proxy measures (such as years of schooling) used in the formal approach. Although years of schooling is a measure of an input into the education system, literacy and numeracy skills directly measure educational outcomes (Osberg 2000). Furthermore, while people’s highest level of educational attainment or years of education remains largely unchanged over the course of their lives, their actual skills may vary at different points in time, depending on how they are used in daily activities. Compared with the social and cultural approach, the functional definition of literacy and numeracy is easier to measure, making it more useful for the empirical analysis in this paper. Functional literacy and numeracy skills of the Australian population were obtained from the Adult Literacy and Lifeskills Survey (ALLS) for 2006. It is only the second survey of its kind for Australia. The first survey, for 1996, contained survey data that were highly aggregated, which restricted its use in exploring links between skills and labour market outcomes. The ALLS includes information for almost 10 000 survey respondents, covering the population aged 15 to 74. Each respondent is assigned a test score for various literacy and numeracy skills. There is also information for each person’s labour market status, education and income. 13 Literacy and numeracy skills measured in the ALLS The ALLS measures several ‘domains’ of literacy and numeracy, which relate to the different types of skills necessary to function in a modern society. These are:
Each skill domain is measured in two different ways. First, based on test responses, each skill is measured on a continuous scale ranging from 0 to 500. Each person is located along this continuum, with those people who have poorer literacy or numeracy obtaining a lower rating than those who have higher literacy and numeracy skills. Each skill is then converted into a discrete skill level, ranging from level 1 (the lowest skill level) to level 51 (the highest skill level). Using document literacy, an example of how levels 1 to 5 are constructed from the values in the 500 point index is provided in box 2.1. An explanation of how a person’s capabilities differ according to each skill level is also provided. 1 An exception is for the problem solving domain, for which there are only four skill levels. Box 2.1 How document literacy levels are defined in the ALLSLevel 1 (Test score = 0–225) Tasks in this level tend to require the respondent either to locate a piece of information based on a literal match or to enter information from personal knowledge onto a document. Little, if any, distracting information is present. Level 2 (Test score = 226–275) Tasks in this level are more varied than those in Level 1. Some require the respondents to match a single piece of information; however, several distractors may be present, or the match may require low-level inferences. Tasks in this level may also ask the respondent to cycle through information in a document or to integrate information from various parts of a document. Level 3 (Test score = 276–325) Some tasks in this level require the respondent to integrate multiple pieces of information from one or more documents. Others ask respondents to cycle through rather complex tables or graphs which contain information that is irrelevant or inappropriate to the task. Level 4 (Test score = 326–375) Tasks in this level, like those at the previous levels, ask respondents to perform multiple-feature matches, cycle through documents, and integrate information; however, they require a greater degree of inferencing. Many of these tasks require respondents to provide numerous responses but do not designate how many responses are needed. Conditional information is also present in the document tasks at this level and must be taken into account by the respondent. Level 5 (Test score = 376–500) Tasks in this level require the respondent to search through complex displays that contain multiple distractors, to make high-level text-based inferences, and to use specialised knowledge. Source : ABS (2006).In the descriptive analysis in this paper (chapters 3 and 4), both the continuous and discrete skill measures are used when presenting results. The econometric analyses (chapters 5 and 6) uses only the discrete skill level, because these skill levels have more interpretable definitions than the continuous variable. For example, level 3 is regarded by the survey developers as the ‘minimum required for individuals to meet the complex demands of everyday life and work in the emerging knowledge-based economy’ (ABS 2006, p. 5). For the analysis in this paper (and as the ABS has done in their summary publication), level 4 and level 5 are grouped together (when using the discrete measure) because few people were assessed at level 5. The various literacy and numeracy skills are highly correlated. More than 70 per cent of the population reported the same document literacy and numeracy skill level (bold numbers in table 2.1). A similar pattern occurs for correlations between other skill variables in the survey. Table 2.1 Correlation between document literacy and numeracyPer cent of population Numeracy Document literacy Level 1 Level 2 Level 3 Level 4/5 TotalLevel 1 14.78 1.67 0.05 0.00 16.50Level 2 5.36 19.39 3.72 0.00 28.48Level 3 0.17 9.78 24.19 3.93 38.07Level 4/5 0.00 0.07 5.19 11.70 16.95Total 20.31 30.91 33.15 15.63 100.00 Source : Productivity Commission estimates based on the ALLS (2006).As well as test scores, the ALLS also has subjective measures of literacy and numeracy skills. For example, respondents were asked to rate their ability to use their reading, writing and mathematical skills at work as being either ‘good’, ‘very good’ or ‘poor’. As noted above, self-assessed indicators of functional literacy and numeracy have potential measurement errors. Furthermore, Finnie and Meng (2005) showed that objective measures of skill consistently gave a better explanation of labour market outcomes (employment and income) than subjective measures did. For these reasons, only the objective test scores of literacy and numeracy skills are used in this paper (for both descriptive and econometric analyses). 3 A profile of literacy and numeracy skills in Australia In this section, the literacy and numeracy skills of Australia’s population in 2006 are explored using the ALLS data. Comparisons are also made over time and with other countries. Following this, the literacy and numeracy skills of specific demographic groups are described. 3.1 Australian literacy and numeracy skills compared over time and with other countries Australian literacy and numeracy skills in 2006 As noted in chapter 2, there is a strong correlation across the different types of skills assessed. Looking at each skill type, up to half of those people surveyed in 2006 (44–50 per cent) had low (level 1 or 2) prose literacy, document literacy or numeracy and almost 70 per cent had low problem solving skills (table 3.1). About one third of the population had level 3 skills for each type of skill (except problem solving). Table 3.1 Distribution of skill levels for working age respondentsaBy skill type, 2006 Skill level (per cent of population) Skill type 1 2 1 and 2 3 4/5 Prose 14.5 29.0 43.5 38.8 17.7 Document 15.5 28.0 43.5 37.1 19.4 Numeracy 19.7 30.0 49.7 32.8 17.5 Problem solving 32.1 35.7 67.8 26.3 5.9 a Working age respondents are persons aged 15–65.Source : ABS (2006).The above information suggests that a substantial proportion (almost 50 per cent) of working age Australians have ‘low’ skills, which is in contrast with 2009 NAPLAN results that reported about 90 per cent of students met basic literacy and numeracy standards. The discrepancy between the NAPLAN test results and the ALLS may be, in part, due to the different age brackets for people tested under NAPLAN (students in years 3, 5, 7 and 9) and the ALLS, which was conducted for persons aged 15–74. More likely, however, is that the NAPLAN tests and the ALLS have different interpretations of the benchmark regarding ‘basic’ or ‘minimum’ skill levels. The COAG Reform Council provides some useful guidance on how to interpret these benchmarks. It states that NAPLAN is designed to measure student performance in meeting the ‘minimum standards’ of literacy and numeracy, whereas the ALLS measures the proportion of working age Australians with a ‘proficient standard’ of literacy and numeracy to effectively participate in society (COAG Reform Council 2009, p. 47). Thus, while some students may have only level 1 or level 2 literacy and numeracy in the ALLS, they may still meet the minimum standard of literacy and numeracy under the NAPLAN definition. Did Australian literacy and numeracy skills increase over the previous decade? Of the five skills measured in the ALLS (2006), only prose and document literacy are directly comparable with the Survey of Aspects of Literacy (SAL) for 1996. Problem solving and health are new dimensions, while numeracy has been expanded. There were small, but statistically significant, changes in both prose and document literacy between 1996 and 2006 (ABS 2006). There was a statistically significant decrease in the proportion of people with level 1 prose and document literacy. This corresponded with an increase in the proportion of people with level 2 prose and document literacy between 1996 and 2006. Level 1 and level 2 are considered to be below the level required to function in daily activities, including work. When looking at skill levels 1 and 2 combined, the proportion of people with low (level 1 or level 2) prose literacy decreased slightly, from 47.4 per cent in 1996 to 46.4 per cent in 2006. Similarly, the proportion of people with level 1 or 2 document literacy decreased from 47.9 per cent in 1996 to 46.8 per cent in 2006. 11 These figures are from the ABS (2006) summary publication, which reported level 1 and level 2 skills separately. It is not known whether the changes are statistically significant. Although the ALLS and the SAL can be used to examine changes over time, the two surveys are not longitudinal in design (which would require the samerespondents to be re-interviewed). However, the cohort analysis presented below is a reasonable measure of the change over time in the populations the two surveys represent. To follow how skills of the population have changed over time, a particular age group (spanning 10 years) in 1996 has been compared with a 10-year older age group in 2006. The synthetic cohort analysis (depicted in figure 3.1), shows that there was lower document literacy for age groups 35–54 in 1996 (who were aged 45–64 in 2006) and higher literacy for those aged 15–24 in 1996 (aged 25–34 in 2006). Determining how skills vary according to age and over time is difficult. Cohort effects and period effects can all influence skill development (Willms and Murray 2007). However, these results give support to a hypothesis of skill depreciation with age and are also consistent with a hypothesis of general skill improvement in the population over time, perhaps because younger people are now undertaking more education. (These are discussed in more detail below.) Figure 3.1 Document literacy and age cohorts1996 and 2006 0.0 0.5 1.0 1.5 2.0 2.5 3.0 1996 (15 to 24yrs) 2006 (25 to 34 yrs) 1996 (25 to 34 yrs) 2006 (35 to 44 yrs) 1996 (35 to 44 yrs) 2006 (45 to 54 yrs) 1996 (45 to 54 yrs) 2006 (55 to 64 yrs) Average document literacy level Data source : Productivity Commission estimates based on the ALLS (2006) and the SAL (1996).How did Australia’s literacy and numeracy skills compare with other countries? The ALLS was conducted as part of a wider, international survey (IALS). There are seven countries for which the 2006 Australian data can be compared. Norway had the smallest proportion of people with skill levels 1 or 2 for prose literacy, document literacy and problem solving (table 3.2). Switzerland had the smallest proportion of people with numeracy levels 1 and 2. Italy had the largest proportion of people with skill levels 1 and 2 across all four measures. (Health literacy results are not available.) Table 3.2 International comparisons of low literacyPer cent of population aged 16–65 with skill levels 1 or 2 Country Prose Document Numeracy Problem solving Australia 43.5 43.5 49.7 67.8 Bermuda 38.1 46.1 54.1 69.9 Canada 41.9 42.6 49.8 68.5 Italy 79.5 80.6 80.2 90.6 Norway 34.1 32.4 40.2 60.8 Switzerland 52.2 49.0 39.3 66.1 United States 52.6 52.5 58.6 nana not applicable.Source : ABS (2006).Australia was ranked fourth on prose literacy, with Norway, Bermuda and Canada having lower rates of prose literacy level 1 or 2. Australia was ranked third on document literacy, with Norway, and Canada having lower rates of document literacy level 1 or 2. For numeracy and problem solving literacy, Australia was ranked third behind Norway and Switzerland. 3.2 How do skills vary across demographic groups? The analysis above has shown that Australia ranked in the middle compared with the selected countries. However, there were many people deemed to have skills below those required for day-to-day living and working, based on the standard set by the survey designers. This section looks more closely at which groups of people have higher and lower skill levels. Literacy and numeracy skills vary between men and women The distribution of people with high and low literacy and numeracy skills varies depending on the particular type of literacy and numeracy being assessed and according to gender. The main differences in particular types of literacy and numeracy between genders (figure 3.2) are: • females have lower levels of numeracy than males (58 per cent of females wereassessed at skill level 1 or 2, compared with 48 per cent for males) • males have lower prose literacy skills, compared with females• females have lower levels of document literacy than males.These differences hold for most age groups (all ages in the case of numeracy) and are consistent with previously observed patterns for other countries (Statistics Canada and OECD, 2005). Figure 3.2 Proportion of people with literacy level 1 or 2, by sex2006 0 10 20 30 40 50 60 70 80 Prose Document Numeracy Problem solving Health Per cent of population Males Females Data source : ABS (2006).Literacy and numeracy skills decrease with age Statistics Canada and OECD (2005, p. 43) state ‘Skills can be acquired, developed, maintained and lost over the lifespan, making the relationship between skills and age complex’. At the aggregate level, an examination of skills according to age suggests that skills of older people are lower than younger people. Using document literacy as an example, skills are highest for 20–24 year olds, as indicated in figure 3.3. Skills appear to decrease as people age. This observation also is apparent with other skill types, and occurs across countries. Figure 3.3 Document literacy score, by age200 220 240 260 280 300 15-19 20-24 25-29 30-34 35-39 40-44 45-49 50-54 55-59 60-64 65-69 70-74 Age Document literacy score Data source : Productivity Commission estimates based on the ALLS (2006).A number of possible explanations for this observation are discussed below: 1. Age and up-skilling. Up-skilling can include formal, and non-formal up-skilling. Formal up-skilling refers to participation in a course that leads towards a certificate, diploma or degree, whereas non-formal up-skilling does not lead towards a certificate, degree or diploma (Satherly and Lawes 2008). As most people undertake formal education until the age of about 20–24, their skills might increase until that age because skill levels increase with higher levels of education. Depending on their literacy engagement after this age, people may maintain, enhance or experience a depreciation in their skills during late and middle age (Willms and Murray 2007). On average, people undertake less formal or non-formal education as they get older, which may explain, in part, the lower skill level of older persons. 2. Labour force withdrawal and skill depreciation. The pattern of skills decreasing as people age (from about the ages of 40–44 onwards) might reflect that older people withdraw from the labour force and do not actively use their literacy and numeracy skills, thereby lending to a depreciation in them. 3. Cohort effects. The quality and quantity of education provided to younger people today might be better than it was at the time when older people obtained their education. If this were the case, then it would be expected that younger people would have higher skill levels compared with other people, all else equal. (This is explored in more detail below.) People with more education have higher literacy and numeracy skills “In most societies, a principal and widely accepted goal of the educational system is to produce a population able to read, write and count’ (Statistics Canada and OECD 2005, p. 60). Therefore, it is not surprising that a large body of empirical research shows that higher educational attainment is associated with higher skills. Figure 3.4 shows the average literacy and numeracy skills for people in Australia, by years of education undertaken (grey line) and qualification (dot points, with average years to complete). Skills appear to increase with the number of years of education undertaken, but at a decreasing rate. Figure 3.4 Literacy and numeracy scorea, by years of formaleducation and highest qualification 2006 150 175 200 225 250 275 300 325 350 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 Years of education Avg. document, prose and numeracy Level 3 Level 2 Level 1 Level 4 Year 11 or lower Diploma or certificate Bachelor degree Postgraduate degree a The literacy and numeracy test score is an average of document, prose, numeracy and problem solving skillindexes. Four years of education includes all people who acquired up to four years of education. 23 years of education indicates people who may have taken 23, or more, years of education. Data source : Productivity Commission estimates based on the ALLS (2006).Undertaking more years of education may not improve skills in the same way for all people. Some individuals may take more time to complete a qualification than others (for instance, if they repeat year 12, or if they change courses at university). Higher educational attainment is associated with higher skills. However, people with year 12 or a degree or higher both have, on average, level 3 skills. Undertaking more years of education than required for a degree does not lead to a noticeable increase in skills. These results might reflect that early years of education (primary and secondary school) primarily serve to improve basic skills needed for day-to-day functioning, whereas higher education (for example, VET or university) is tailored to more vocational or job-specific skills, which do not have a noticeable impact on functional literacy and numeracy. In this respect, it might also be useful to examine information from the NAPLAN results to develop an understanding of skill deficiencies in the formative years of a person’s education. (This, and other areas for further research, are mentioned in chapter 7.) Returns to education were unchanged in the past decade, but people are more highly qualified It was mentioned above that an education cohort effect might explain the increase in skills between 1996 and 2006. To examine this, the distribution of document literacy skill levels by qualification, for both 1996 and 2006, is shown in figure 3.5. Higher qualifications are associated with higher skill levels –– the proportion of people with level 4 or 5 document literacy is much higher for those with a degree compared with other levels of education. Figure 3.5 Distribution of document literacy skills and qualifications1996 and 2006 0% 20% 40% 60% 80% 100% 1996 2006 1996 2006 1996 2006 1996 2006 Degree or higher Diploma or certificate Year 12 Year 11 or lower Level 4/5 Level 3 Level 2 Level 1 Proportion of people with qualification Data source : Productivity Commission estimates based on the ALLS (2006) and the SAL (1996).For the same qualification, the proportion of people with document literacy above level 2 did not change much between 1996 and 2006. This suggests that any cohort effect from a change in the quality of education (between 1996 and 2006) is small.However, there was a shift in the proportion of people with higher levels of education (depicted by the lines in figure 3.5). For example, 20 per cent of the population held a degree in 2006 compared with 15 per cent in 1996. So there is an education cohort effect –– an increase in the quantity of education taken –– thatmight partly explain the overall increase in skills between 1996 and 2006. Skills of immigrants compared with Australian born people A number of overseas studies have shown that skills vary according to country of birth and, for immigrants, vary according to their time of arrival. Satherly, Lawes and Sok (2008) found that, for both the United States and New Zealand, native born people had higher skills than immigrants. In the United States, recently arrived immigrants (those who arrived within five years at the time of the survey) had higher skills than established immigrants (those who arrived more than five years ago), but the opposite was the case for immigrants in New Zealand. The skills of immigrants by both country of birth and time of arrival can also be explored for Australia using data from the ALLS. Skills of immigrants do not vary by period of time they have been in Australia Recent immigrants are, on average, 31 years old, whereas established immigrants are 48 years old. (Australian born people were 40 years old, on average, in 2006). As shown above, there is evidence indicating that older people have lower literacy and numeracy skills than younger people. Therefore, the skills of recent immigrants, established immigrants and Australian born people were compared for only 20–44 year olds. This age group was chosen because, after these ages, skill levels decrease noticeably. The sample size for this group is still large enough to make reliable judgements. After controlling for age, there is not much difference between the prose literacy skills of recent immigrants and established immigrants (figure 3.6). Thus, the period of time immigrants have spent in Australia does not appear to influence their skill levels. However, compared with the Australian born population, the skills of all immigrants are lower (even after controlling for age). Figure 3.6 Prose literacy, by period of time immigrant has been inAustralia a20–44 year olds 0% 20% 40% 60% 80% 100% Recent Established Australian born Level 4/5 Level 3 Level 2 Level 1 a A ‘recent’ immigrant is defined as having arrived in Australia within five years of the date the survey wasundertaken, while an ‘established’ immigrant is someone who arrived more than five years from when the survey was undertaken. Data source : Productivity Commission estimates based on the ALLS (2006).People born in a non-English speaking country tend to have lower skills The skills of immigrants vary significantly, according to their country of birth. In particular, immigrants born in countries the ABS defines as a main English speaking country (including the United States, United Kingdom, Canada and South Africa) have much higher average literacy and numeracy skills than immigrants from other (mainly non-English speaking) countries. That is not unexpected, because the tests were conducted in English. The literacy and numeracy skills of immigrants from English speaking countries are higher than those of Australian born people as a whole (figure 3.7). Immigrants from main English speaking countries comprise about 36 per cent of all immigrants. Figure 3.7 Prose literacy, by country of birtha0% 20% 40% 60% 80% 100% Australia Main English speaking Other Level 4/5 Level 3 Level 2 Level 1 a Main English speaking countries are defined by the ABS as the United States, Canada, South Africa, NewZealand, Republic of Ireland and the United Kingdom. Data source : Productivity Commission estimates based on the ALLS (2006).Variations in immigrants’ skills might be influenced by the quality of schooling in the country of origin. The ALLS also has data on where a person obtained their highest educational qualification. It was found that people who obtained their qualification from a non-English speaking country tended to have lower skills compared with those with a qualification from an English speaking country. This finding is consistent with a study comparing results from a range of countries for which data were available: Education credentials do not necessarily translate into functional levels of literacy, numeracy and problem solving skills in the official language(s) of the host country. This is especially the case if the credentials were attained abroad in a language other than that used in the host country. (Statistics Canada and OECD 2005, p. 209) Having an English speaking background not only affects literacy and numeracy skills, but also labour market outcomes. For example, the Commission (PC 2006b) found earnings of immigrants to be positively related to their English speaking ability, after controlling for factors such as educational attainment. The effect of non-English speaking background on labour market outcomes is explored in more detail in the econometric analysis presented in chapter 6. 4 Literacy and numeracy skills and labour market outcomes Chapter 3 considered how literacy and numeracy skills vary across different demographic groups. It was shown that some groups had much lower literacy and numeracy skills than others, suggesting there is some potential to raise the skills of those groups of people. This chapter considers the relationship between literacy and numeracy skills and labour market outcomes, to help identify the potential benefits from improving literacy and numeracy. Specifically, the relationship between literacy and numeracy skills and the following labour market outcomes are explored: labour force participation; occupation; and income. It will be shown that people who have higher literacy and numeracy skills generally have much better labour market outcomes than those with lower skills. 4.1 Literacy and numeracy skills and labour force participation While participation depends on a range of factors, including the presence of children (Cai 2010), for most people having higher human capital (including literacy and numeracy) will encourage greater labour force participation. People with higher functional literacy and numeracy skills are likely to achieve greater returns from working than lower skilled people. Therefore, the higher people’s skills are, the more likely they are to participate in the labour force, all else equal. For various age groups, the document literacy test score according to labour force status is presented in figure 4.1. (While the results presented in figures 4.1 and 4.2 are for document literacy, a similar pattern emerges for other skill types measured in the ALLS.) A few observations can be made. Those in the labour force have higher document literacy than those who are not in the labour force. This holds across all age groups. The difference between document literacy of those in and those not in the labour force varies with age –– the difference is smaller for younger people (aged less than 30) compared with older people. Labour force participation might affect skills if working utilises and maintains a person’s skills. If that were the case, the results might reflect that older people have been out of work for a longer period, so their skills might have decreased compared with younger workers. Figure 4.1 Document literacy score, by labour force status and age175 200 225 250 275 300 325 15-19 20-24 25-29 30-34 35-39 40-44 45-49 50-54 55-59 60-64 65-69 70-74 Age Document literacy score In labour force Not in labour force Level 2 Level 3 Data source : Productivity Commission estimates based on the ALLS (2006).Another way this can be examined is to look at skills and the participation rate. There is a strong correlation between the labour force participation rate and document literacy (figure 4.2). This gives some support to the idea that people’s skills decline if they do not participate in the workforce. (However, as shown previously, literacy and numeracy skills decline with age, regardless of labour force status.) Figure 4.2 Document literacy, by participation and age200 225 250 275 300 15-19 20-24 25-29 30-34 35-39 40-44 45-49 50-54 55-59 60-64 65-69 70-74 Age 0 25 50 75 100 Document literacy (score - LHS) Participation rate (Per cent - RHS) Level 3 Level 2 Data source : Productivity Commission estimates based on the ALLS (2006).4.2 Literacy and numeracy skills and occupation It would be expected that, all else equal, people who have high literacy and numeracy skills are likely to be employed in professions that require the use of those skills. Occupational data in the ALLS showed that, for those people with an average document literacy, prose literacy and numeracy skill level of 3 or more, most were employed as professionals, managers, and clerical and administrative workers respectively (figure 4.3). They were least represented as machinery operators/drivers and labourers. Conversely, people with skill level 1 or 2 were most likely to be employed as labourers and technicians/trade workers. Figure 4.3 Occupational distribution, by average skill levela0 5 10 15 20 25 30 35 Manager Professional Technician & Trade Community & Pers. Services Clerical & Admin Sales Machinery Operator & Driver Labourer Per cent Level 1 or 2 Level 3, 4 or 5 a Average skill level is equal to the average test score for document literacy, prose literacy and numeracy(scale 0-500), converted to the equivalent level (as measured by the ABS –– see chapter 2). Data source : Productivity Commission estimates based on the ALLS (2006).Within each occupation, the proportion of people with average literacy and numeracy skill levels 1 or 2, level 3 and levels 4 or 5 are shown in figure 4.4. Fewer than 30 per cent of managers had low (level 1 or 2) literacy and numeracy skills. In contrast, about two-thirds of machinery operators/drivers and labourers had level 1 or 2 literacy and numeracy skills. SKILLS AND LABOUR MARKET OUTCOMES 33 Figure 4.4 Skill distribution, by occupation0 20 40 60 80 100 Manager ProfessionalTechnician & Trade Community & Pers. Services Clerical & Admin Sales Machinery Operator & Driver Labourer Per cent Level 4/5 Level 3 Level 1/2 a Average skill level is equal to the average test score for document literacy, prose literacy and numeracy(scale 0-500), converted to the equivalent level (as measured by the ABS –– see chapter 2). Data source : Productivity Commission estimates based on the ALLS (2006).The ALLS also has information on whether people agree that their reading, writing and maths skills are good enough to perform their job. Using this information, it appears that there is a greater return from improving the literacy and numeracy skills of lower skilled workers than higher skilled workers. For example, about 15 per cent of workers with level 1 numeracy stated that their maths skills were not good enough to do their job (compared with about 5 per cent of workers with skill level 2 and just one per cent of workers with level 3 numeracy). Thus, the economic payoff from improving workers’ skills –– that is, having a more capable/effective workforce ––– would be larger from improving workers’ skills from level 1 to level 2 compared with further improvements of relatively high-skilled workers. 4.3 Literacy and numeracy skills and income Understanding the links between literacy and numeracy skills and income/wages is important, because wages can be used to measure productivity (Forbes, Barker and Turner 2010). 34 LITERACY ANDNUMERACY SKILLS & LABOUR MARKET Factors explaining the relationship between literacy and numeracy skills and income Marks (2008) outlined demand, supply and institutional factors that explain how higher education and skills may lead to higher wages, as discussed below. Supply-side Individuals invest in education and training to improve their skills. Employees with higher skills (obtained through education) are expected to be more productive and can earn higher wages than less-skilled workers, all else equal. Demand-side Employers may view a person’s educational qualification as a signal that a worker is more productive than others, and offer higher wages. As Leigh (2008) notes, if education is merely a credential then it would signal ability, without raising productivity. Institutional factors In Australia, many professional and technical occupations have pay rates linked to qualifications. For example, industrial award structures specify that wage rates for workers with certain qualifications are higher than wage rates for unqualified workers. Empirical relationship between literacy and numeracy skills and income The ALLS data supports the theoretical relationship set out above –– people with higher skills earn more than people with lower skills. On average, weekly income is higher for more highly skilled workers (figures 4.5 and 4.6 for men and women, respectively). For men, there is a larger increase in income from moving from skill level 1 to level 2, compared with increases in income from moving at level 2 to level 3 (or level 3 to level 4/5). For women, the opposite occurs, with the largest increase in average weekly income occurring in moving from skill level 3 to level 4/5. SKILLS AND LABOUR MARKET OUTCOMES 35 Figure 4.5 Male weekly income distribution,a by average skill levelb15–64 year olds 0 500 1000 1500 2000 2500 3000 Level 1 Level 2 Level 3 Level 4/5 Weekly income from main job ($) a Average weekly income is shown by the grey squares. Bars show the average income range between thetenth and ninetieth deciles. The triangles are median income points. b Average skill level is equal to theaverage test score for document literacy, prose literacy and numeracy (scale 0-500), converted to the equivalent level (as measured by the ABS –– see chapter 2). Data source : Productivity Commission estimates based on the ALLS (2006).Figure 4.6 Female weekly income distributiona, by average skill levelb15–64 year olds 0 500 1000 1500 2000 2500 Level 1 Level 2 Level 3 Level 4/5 Weekly income from main job ($) a Average weekly income is shown by the grey squares. The black bars show the average income rangebetween the tenth and ninetieth deciles. The triangles are median income points. b Average skill level is equalto the average test score for document literacy, prose literacy and numeracy (scale 0-500), converted to the equivalent level (as measured by the ABS –– see chapter 2). Data source : Productivity Commission estimates based on the ALLS (2006).36 LITERACY ANDNUMERACY SKILLS & LABOUR MARKET However, these results are only for weekly earnings, and do not capture the differing amounts of hours worked by men and women, or hours worked across the skill distribution. The average hourly wage rate for a worker with skill level 1 is about 60 per cent of that earned by a worker with skill level 4/5 (table 4.1). For men, hourly wage rates increase at each skill level, but the largest increase in hourly wages occurs at the higher end of the skill distribution. This is the opposite for women, although the result for skill level 2 should be treated with caution (see note b in table 4.1). Table 4.1 Wage rate, by average skill levelaDollars per hour in main job, 25–64 year olds Males Females Total Level 1 22.13 16.87 19.69 Level 2 24.69 30.71 b 26.63Level 3 30.21 26.54 26.82 Level 4/5 36.64 27.51 32.23 a Average skill level is equal to the average test score for document literacy, prose literacy and numeracy(scale 0-500), converted to the equivalent level (as measured by the ABS –– see chapter 2). Results are survey weighted. b Estimate had a very large standard error compared with other estimates, and should betreated with caution. Source : Productivity Commission estimates based on the ALLS (2006).ECONOMETRIC METHOD AND DATA 37 5 Econometric method and variable construction The analysis in chapter 4 highlighted that people with higher literacy and numeracy skills are more likely to participate in the workforce, be employed in more highly skilled jobs and earn more, compared with people who have lower skills. In chapter 3 it was suggested that people’s skills vary according to demographic factors such as country of birth, age, gender and educational attainment. These and other individual characteristics are also likely to affect labour market outcomes, so cross-tabulations (between skills and labour market outcomes) will not accurately predict how much an improvement in literacy and numeracy skills can improve labour market outcomes. In this section of the report, multivariate econometric models are presented which control for demographic factors to estimate the effect of literacy and numeracy skills on the following labour market outcomes: • labour force participation• wages.Following this, a description of the variables used in the econometric analyses is presented. Modelling results are reported in chapter 6. 5.1 Econometric models of labour force participation and wages Econometric models of labour force participation and wages can help answer the following research questions: • What is the effect of increasing literacy and numeracy skills onparticipation/wages, holding other factors (including education) constant? • Do models of participation that use only proxy measures of skills accuratelymeasure the effect of human capital on participation and wages? • How important are literacy and numeracy skills, relative to other indicators ofhuman capital (for example, education and labour market experience) in raising labour force participation and wages? 38 LITERACY ANDNUMERACY SKILLS & LABOUR MARKET • Does the impact of literacy and numeracy skills on participation or wages varyalong different points of the skill distribution, and are there differences between genders? The framework used in the analysis draws upon approaches used by other researchers including Chiswick, Lee and Miller (2003) for labour force participation and Barrett (2009) for wages. Both of those papers used Australian data, allowing for comparisons with the results in this paper. Estimating the effect of literacy and numeracy skills on labour force participation Two models of labour force participation are estimated, using a similar approach to Chiswick, Lee and Miller (2003). In the first instance, a ‘traditional’ human capital model is estimated. That model assumes that labour force participation is a function of education and potential labour market experience. The model 1 takes the form:LFP = α0 + α1 ED + α2 X + ε (1)where: LFP = labour force participation (0 or 1)ED is a vector of educational attainment variables (section 5.2)and X is a vector of variables representing factors likely to affectparticipation (including age, marital status, children –– see output in appendix B for full list). In this specification, education is an indicative measure of a person’s skill level. Such an assumption might be valid under the ‘formal’ or ‘abstract’ approach to literacy and numeracy, which assumes that years of education is a good measure of a person’s skills (chapter 2). The functional approach to literacy and numeracy –– which is consistent with a human capital framework –– suggests that literacy and numeracy are only loosely correlated with education. The empirical analysis presented in chapter 3 supported this framework. Education may enhance literacy and numeracy skills, but it may also be important for developing other skills relevant for work –– for example, affective skills of cooperation and perseverance (Chiswick, Lee and Miller 2003). 1 In their analysis, Chiswick, Lee and Miller (2003) used potential labour market experience as a control variable. Age is used here, but in practice both are highly correlated as potential labour market experience is defined as age minus years of education minus 5. ECONOMETRIC METHOD AND DATA 39 Therefore, estimating the effect of education and skills on participation separatelygives additional insight that traditional human capital models do not. In particular, inclusion of the skills variable allows us to estimate the: • effect that education has on participation, after controlling for differences inpeople’s functional skills • relative importance of the various skills needed in the workplace (for example,functional literacy and numeracy skills and other skills that education provides). Therefore, a second model of participation is estimated, which explicitly controls for functional literacy and numeracy skills: LFP = β0 + β1 ED + β2 LitNum + β3 X + ε (2)where: LitNum = Literacy and numeracy skill level (explained in section 5.2).In this specification, the coefficient β2 measures the effect of improving literacy andnumeracy skills on participation. Education is modelled as having a direct effect on participation ( β1 ). However, education might also indirectly effect participation, ifundertaking more education leads to greater skills. Education is likely to improve literacy and numeracy skills, but those skills may also be developed, or enhanced, outside of the school sector. Equation 2 does not distinguish how skills are developed. The two models above are estimated because important findings can be obtained by comparing results. If education is a good proxy for skills, then inclusion of the skills variable (in equation 2) should not add to the explanatory power of the model. Furthermore, it may cause collinearity problems –– either the literacy and numeracy skill variable, or education variable, would not be significant. If, however, literacy and numeracy skills are influenced by education (but they are not the same) then both variables would be significant (in equation 2). The magnitude of the education coefficient would diminish if education influences literacy and numeracy, with education now a measure of the effect from other skills that education provides on the likelihood of participation. Participation is a binary variable (1 if in the labour force, 0 otherwise). The demographic factors X are based on those commonly found in the literature (seemodel results in appendix B for those variables used in the analysis, and a description of each variable in appendix A). Previous research has used logit and probit models to estimate labour force participation. Greene (2008) states that there is no theoretical reason to prefer one model over the other. In the analysis here, the labour force participation equations 40 LITERACY ANDNUMERACY SKILLS & LABOUR MARKET were estimated with a probit and logit model. Results were very similar, and therefore are reported only for the probit model of labour force participation (presented in chapter 6 and appendix B). The probit model was chosen for consistency –– as explained below, it was also used as a first step in some of the wages models estimated. Ability bias may affect results A problem commonly identified in the human capital literature ‘is that higher ability individuals may systematically choose more schooling, leading to an upward bias in the estimated return to schooling’ (Hanushek and Zhang 2006, p. 2). Put another way, models that do not explicitly control for ability may overestimate the return to education –– people who undertake more education may choose to do so because they have higher ability than those people who do not undertake education. The inclusion of a skills measure may partly reduce this ability bias, as people with higher ability are likely to have higher skills. However, as Barrett (2009, p. 6) notes, the literacy and numeracy tests ‘drew on cognitive skills typically used in daily activities, hence the emphasis on ALLS measuring skills of daily living, rather thanunderlying abilities or potential’. Insofar as the education and skills variables used in the analysis do not adequately capture a person’s innate ability, motivation or potential, then the results may be biased upwards. There is likely to be some ability bias in the results. People with higher ability are more likely to increase their education which, in turn, is likely to increase their skills more than otherwise. Ability bias can be controlled for by following individuals and their skill development over time. However, because the ALLS data are cross-sectional, they cannot be used to control for underlying ability. 2The potential problem of ability bias, in practice, might not have a material effect on the results. Laplagne, Glover and Shomos (2007) used a panel model of labour force participation (which accounts for unobserved factors such as ability) and estimated that having a degree increased the likelihood of participation for females by 20 percentage points compared with a female who only had year 11 or lower education. This compared with a 16 percentage point increase when estimated with a standard model. The differences in model results were smaller when estimated for males, and smaller again when estimated for other qualifications (because the impact of other qualifications on participation is smaller than from having a degree). Therefore, any ability bias present in the data is unlikely to change the qualitative findings. 2 Ability bias may also affect results for the wages model presented below. ECONOMETRIC METHOD AND DATA 41 Estimating the effect of literacy and numeracy skills on wages To estimate the effect of literacy and numeracy skills on wages, a model developed by Mincer (1974) is used, where wages are modelled as a function of human capital variables including potential experience in the labour market and education. That model takes the form: Log( W) = α0 + α1 ED + α2 EXP + α3 EXP2 + α4 X + u (3)where: W is the hourly wage rateED is a vector of educational attainment measuresEXP is potential work experienceand X is a vector of variables likely to affect wages (see output results inappendix B for full list). This model is analogous to equation 1, used to estimate the effect of education on participation. Like that model, equation 3 is then re-estimated to include the effect of functional literacy and numeracy skills: Log( W) = β0 + β1 ED + β2 LitNum + β3 EXP + β4 EXP2 + β5 X + u (4)where: LitNum is a measure of literacy and numeracy skills (defined above).If workers with higher functional skills are likely to earn higher wages regardless of their level of education then in equation 3, which only examines the effect of education and income, the observed effect of education on income will reflect the effect of both education and skills (Leigh 2008). Including a variable for functionalliteracy and numeray skills (equation 4) enables the effect of these skills to be estimated separately from education. Therefore, the addition of the skills variable is expected to reduce the coefficient for education (because skills are now modelled separately). Sample selection bias and the Heckman model Sample selection bias can arise if the group of observations for which a model is estimated is not taken from a random sample. In the wages model, the hourly wage rate is the dependent variable. However, wage rates are only observed for people who are employed. As people who are employed tend to have characteristics different to those who are not in the labour force or unemployed, excluding these groups results in a non-random sample being used, which may bias results. 42 LITERACY ANDNUMERACY SKILLS & LABOUR MARKET A large literature has evolved to address this potential problem, and a common approach is to run a two-step model, first developed by Heckman (1979). Conceptually, a ‘selection equation’ is first estimated for labour force participation, which has a binary outcome (1 or 0). An ‘inverse Mills’ ratio is estimated from this equation, and incorporated into a second equation –– the earnings equation –– as a correction term. A ‘selection effect’ is present if the two error terms from each equation are correlated. By including the correction term, coefficients are adjusted to take account of the selection effect. In this paper, wage models were first estimated using ordinary least squares (OLS) on the sample of employed persons only. Next, Heckman models were used to estimate a selection equation (on all persons), and a wage equation (for employed persons). The selection equation uses a probit model specification for labour force participation. Although results showed no evidence of a sample selection error, the Heckman model results are presented in chapter 6 as the preferred estimates. For completeness, both the Heckman and standard OLS model results are presented in full (appendix B). The model results were very similar between the OLS and Heckman models. 5.2 Variables used in the analysis This section describes how the main variables of interest used in the analysis were constructed. Appendix A contains a full list of variables used in all models, including their mean and standard deviations. Labour force participation Participation is treated as a binary variable, taking the value 1 for persons in the labour force (employed and unemployed persons) and 0 otherwise. Wages Wages are estimated using a measure of the hourly wage rate. The hourly wage rate is defined as weekly income divided by number of hours worked per week. There are two income measures in the survey data that can be used. One is income from all sources (including government allowances). Another is based on income from a person’s main job only. Similarly, hours worked are reported for a person’s ECONOMETRIC METHOD AND DATA 43 main job only, and for all jobs. In the analysis, the hourly wage rate is obtained using the income and hours data pertaining to a person’s main job only. Explanatory variables Explanatory variables are those commonly found in the labour supply literature. Only the human capital variables are described in detail below, as it is the effect of those variables on participation and wages that is the primary focus of this paper. Literacy and numeracy skills There are five different skills formally tested for in the ALLS. In addition, there are subjective measures of skills, but these were not used in the analysis (chapter 2). There are two broad approaches to account for skills in the modelling. First, a separate variable could be included for various skills (for example, document literacy, prose literacy, and numeracy test scores). However, there is a strong correlation between each skill variable (table 2.1) and there may be collinearity problems if all are included. In their analysis, Chiswick, Lee and Miller (2003) found that only one or two variables were needed to obtain most of the model’s explanatory power. A problem with that approach, however, is that it is difficult to determine which skill(s) should be included and which should not. A second approach is to construct an index of literacy and numeracy skills by combining the measures that are in the survey. A disadvantage with this approach is that combining the variables makes it difficult to isolate the effect of numeracy from, say, prose literacy on labour market outcomes. The aim of this paper is to identify the effect of overall functional literacy and numeracy skills on labour market outcomes, and not necessarily the effect of particular components within these functional skills. Therefore, the second approach is the one chosen in the analysis. This method has also been used by others (Barrett 2009; Green and Riddell 2001; Hanushek and Zhang 2006), primarily because the skills are highly correlated with each other. A single skill variable capturing a person’s literacy and numeracy skills was constructed as follows: 1. The principal component of the document literacy, prose literacy and numeracy test scores (0–500) was estimated. The indicator of problem solving skill was not included in estimation as it is not a measure of functional literacy or numeracy. 44 LITERACY ANDNUMERACY SKILLS & LABOUR MARKET Furthermore, it is only aggregated to four levels, so it cannot be converted into a skill level 1 to 5 in the same way the other variables are assigned a skill level (see point 4 below). 2. The first principal component (which accounted for about 96 per cent of variation and had almost equal weights for each of the three test scores) was used to weight each of the three skills above (see table 5.1 for principal component analysis). The second and third principal components were not used, as their additional explanatory power was negligible, and the different signs on the weights made their interpretation difficult. 3. The resulting test score was re-indexed to a scale of one to 500, by dividing the aggregate test score by the sum of the principal component weights. 4. The test score was converted into five categorical levels, using the same interval points as in the ABS survey. 5. The following binary variables were also created: (a) Skill level 2 = 1 if skill level 2, 0 otherwise (b) Skill level 3 = 1 if skill level 3, 0 otherwise (c) Skill level 4/5 = 1 if skill level 4 or 5, 0 otherwise Table 5.1 Principal component analysis for skills variableType of literacy Component 1 Component 2 Component 3 Proportion explained Cumulative Document literacy 0.5818 -0.2618 -0.7701 0.9604 0.9604 Prose literacy 0.5721 0.8047 0.1586 0.0289 0.9894 Numeracy 0.5782 -0.5328 0.6179 0.0106 1.0000 Source : Productivity Commission estimates based on the ALLS (2006).In each model that was estimated, either the continuous literacy and numeracy measure (defined in point 3) was used, or the binary variables (defined in point 5) were used. The continuous measure has the benefit of providing more data points, while the skill levels approach provides a more meaningful interpretation of what is being estimated. For example, with only skill level 1 excluded from the model, the coefficient for skill level 3 estimates the effect of increasing functional literacy and numeracy skills from level 1 (representing a person with the lowest level of literacy/numeracy) to level 3 –– the minimum level required for a person to effectively participate in the workforce. The preferred approach in the analysis, and presented in chapter 6, was to use the skill level variables. (However, full estimation output using a continuous skill variable can also be found in appendix B.) The resulting vector of skill variables ECONOMETRIC METHOD AND DATA 45 (defined as LitNum in section 5.1) should be interpreted as measuring overallfunctional literacy and numeracy (as defined in chapter 2). Barrett (2009) and others have also said that this variable can be interpreted as measuring cognitive skills. Education Four categories of educational attainment were used: Year 11 or lower; Year 12; Diploma or Certificate; and Degree or higher. These were aggregated from more detailed levels of education reported in the survey (table 5.2). Years of education was not used because, as discussed above and in other studies, the time taken to complete a course of study can vary significantly among individuals. Year 11 or lower is the benchmark from which the effects of the other three categories of highest education level were estimated and compared. As such, Year 11 or lower does not appear in the modelling results presented in chapter 6. Table 5.2 Educational attainment variables used in the modellingSurvey data response Aggregated educational level of attainment Postgraduate degree Degree or higher Graduate Diploma/Graduate Certificate Degree or higher Bachelor Degree Degree or higher Advanced Diploma/Diploma Diploma/Certificate Certificate III/IV Diploma/Certificate Certificate I/II Year 11 or lower Certificate not further defined Year 11 or lower Year 12 Year 12 Year 11 Year 11 or lower Year 10 Year 11 or lower Year 9 Year 11 or lower Year 8 or below including never attended school Year 11 or lower Source : Based on the ALLS (2006).The particular education levels were chosen because they were also used to analyse the effects of education (and health) on labour force participation by Laplagne, Glover and Shomos (2007) and on wages by Forbes, Barker and Turner (2010). Therefore, modelling results can be compared with the results from those papers. 5.3 Estimation sample Each model was estimated separately for males and females. This was done for a number of reasons. The decision to participate is likely to vary according to sex –– 46 LITERACY ANDNUMERACY SKILLS & LABOUR MARKET females typically work less after the birth of a child. Thus, the impact of some variables on participation and wages is likely to differ for men and women. In particular, the effect of education on the likelihood of participation and on wages has been shown to vary in its magnitude for men and women (Laplagne, Glover and Shomos 2007; Forbes, Barker and Turner 2010). Thus, for the variables of interest in this analysis –– education and literacy –– it is useful to examine their effects on men and women separately. The sample was restricted to 25–64 year olds. Educational attainment is a variable of interest, and was estimated using indicators for highest level of educational attainment a person has completed. As many people under 25 might not have completed their highest level of education (Leigh 2008), they were excluded from the analysis. Similarly, people aged 65 and over were excluded as the majority of that group would have reached pensionable age. Unweighted data were used in estimation. Models were estimated with Stata, and processed using the ABS’s Remote Access Data Laboratory (RADL). In the next chapter, results from the econometric models above are presented. (Full estimation output is in appendix B.) MODELLING RESULTS 476 Modelling results In this section of the paper, econometric results for the models of labour force participation and wages are presented. The focus of the results is for the marginal effects of education and literacy and numeracy skills on labour force participation and wages. Full estimation output (including coefficients and marginal effects for all variables) is in appendix B. 6.1 Labour force participation results Section 5.1 set out two models of labour force participation –– one which included literacy and numeracy skills (equation 2) and one which did not include those skills (equation 1). Econometric results from those models are presented below. As explained in chapter 5, the literacy and numeracy variable should be interpreted as measuring people’s overall functional literacy and numeracy skills –– not a specific type of literacy or numeracy. Effects of education for different model specifications The marginal effects 1 of educational attainment for equation 1 (does not control forliteracy and numeracy skills) are presented in table 6.1. Table 6.1 Marginal effects of educationa on participation in differentmodel structures Men Women Explanatory variable Education only (Equation 1) With skills (Equation 2) Education only (Equation 1) With skills (Equation 2) Year 12 1.56 -0.01 8.13*** 5.65*** Diploma/Cert 4.07*** 2.93*** 13.08*** 10.53*** Degree 5.20*** 2.78** 19.11*** 14.90*** a Education levels are compared with a base level of year 11 or lower educational attainment.*** significant at 1 per cent, ** 5 per cent and * 10 per cent. Source : Tables B.1 and B.2.1 All marginal effect estimates are calculated at the mean of the variable under consideration. 48 LITERACY ANDNUMERACY SKILLS & LABOUR MARKET Those results are of the expected sign, and consistent with other studies. The marginal effects on participation from having a degree relative to having year 11 or lower education were estimated to be 5.2 percentage points and 19.1 percentage points for men and women respectively. These compare with results from a multinomial logit model estimated by Laplagne, Glover and Shomos (2007) of 8.6 percentage points and 19.7 percentage points for men and women respectively. As explained in chapter 5, if education and skills are synonymous (equation 1), then there would be collinearity problems when equation 2 is estimated –– either the skills or the education variables may be insignificant. Table 6.1 shows the marginal effects for educational attainment when skills are included in the model (equation 2). Compared with results from equation 1, it can be seen that marginal effects are reduced by about one quarter when skills are included. These results imply that a ‘traditional’ model of human capital, which uses education only to proxy skills, might overestimate the direct effect of education on participation. Put another way, about one quarter of the effect education has on participation (in traditional human capital models) occurs because the more highly educated are also more highly skilled. (Education may improve literacy and numeracy skills, but those skills can also be obtained from other means. The model does not examine the factors affecting skills.) As will be shown below, the marginal effects for all of the skills variables (and most of the education variables) are statistically significant in equation 2. Furthermore, the explanatory power of the model was improved (by about 1 percentage point, for both men and women) when the functional literacy and numeracy skills variable was included in estimation. Therefore, a model which assumes that education may enhance functional literacy and numeracy, but is not a direct substitute for thoseskills, is the more appropriate specification. Effects of literacy and numeracy skills on participation In the analysis below, the focus turns to how skills affect participation, so results are presented only for equation 2. Figure 6.1 presents the marginal effects of skills (and educational attainment) on labour force participation. MODELLING RESULTS 49Figure 6.1 Marginal effects of education and skills on participationEducational attainment relative to year 11 or lower, literacy and numeracy skills relative to level 1 a-5 0 5 10 15 20 Year 12 Diploma or Certificate Degree or higher Level 2 Level 3 Level 4/5 Increased probability of participation (ppt) Men Women a Bars show the 95 per cent confidence interval for the marginal effects, which were calculated at the mean. If,for a given variable, the bars overlap, then those estimates are not statistically different at the 5 per cent level of confidence. If a bar reaches the horizontal axis, that marginal effect is not statistically significant at the 5 per cent level of confidence. Data source : Tables B.1 and B.2.The following observations regarding literacy and numeracy skills can be made: • Improving functional literacy and numeracy from level 1 to level 2 or above hasa positive, and statistically significant, impact on labour force participation, for both men and women. • The increase in participation that occurs from improving these skills is greaterfor women than for men (consistent with the effects of greater education, and likely to occur because of the higher participation rate for men). • There is only weak evidence that the effect (on participation) from animprovement in literacy and numeracy skills varies along the skill distribution, with differences between genders. – For women an increase in skills from level 1 to level 2 raises participation by 11 percentage points. Raising skills from level 1 to level 3 (or level 4/5) raises participation by about 15 percentage points. Thus, the largest additional increase in participation occurs from improving lower skilled50 LITERACY ANDNUMERACY SKILLS & LABOUR MARKET workers’ functional literacy and numeracy. 2 (Note, however, that themarginal effect of increasing skills from level 1 to level 2 is not statistically different than from increasing skills from level 1 to level 3). – For men, an improvement in skills from level 1 to level 2 raises participation by almost 4 percentage points, and from level 1 to level 4/5 raises participation by about 6 percentage points. So, there is a more even effect on participation from improving skills along the distribution for men than there is for women. Compared with raising educational attainment, improving people’s skills leads to a relatively large increase in participation. For example, raising skills from level 1 to level 2 has a larger effect on participation than from increasing educational attainment from year 11 or lower to year 12 or a diploma/certificate (and a larger effect than from raising educational attainment to a degree for men). To put that into context, the time taken to complete a degree or higher is roughly seven years longer than the time taken to complete year 11 or lower (figure 3.4). The joint effect from improving education and improving literacy and numeracy skills was not formally estimated in the models (this would require an interactive term for education and skills to be included). However, the results indicate that having higher education and greater literacy and numeracy skills is likely to lead tothe largest increases in participation. For example, if a person has low skills and low education, then increasing education increases the likelihood of participation. The likelihood of participating is increased further if the person also increases his or her literacy and numeracy skills. It is likely that education does improve skills, so the cumulative effect of increasing education is likely to be greater than the predicted estimate for education alone. The effects of education and skills were robust to different model specifications. For example, years of education was used as an alternative to educational attainment, and the continuous literacy/numeracy skill test score (0–500) was used in other variations of the models presented here. The key results did not change. In particular, the effect of improving skills on participation was stronger for women than for men, and statistically significant across all models. Results for literacy and numeracy skills are also consistent with other studies. Chiswick, Lee and Miller (2003) found that document literacy and (self-assessed) 2 Strictly speaking, the effect on participation from increasing skills from level 3 to level 4/5 is not the difference between the marginal effects of skill levels 3 and 4/5 presented in figure 6.1. That would require re-estimating the model with level 3 as the base skill level. Alternative models, with different skill level bases, were estimated for comparison and gave similar results to the differences in marginal effects between skill levels above. MODELLING RESULTS 51mathematical ability both had a positive and statistically significant effect on participation, using 1996 Australian data. They also found the direct effect of education to be overestimated (by up to 50 per cent) if skills are not controlled for. Other results A number of other explanatory variables were included in the estimation. This section briefly reports some of those results (appendix B contains full estimation output). In chapter 3, it was shown that skills vary according to country of birth. The models estimated include explanatory variables for being born in either a main English speaking country, or a non-English speaking 3 country, relative to being born inAustralia. Being born in a non-English speaking country had a negative effect on female participation (it reduced the likelihood of participation by 10 percentage points in equation 1). However, the negative effect reduced markedly once skills were controlled for (to minus 5 percentage points in equation 2). These results demonstrate that the negative effect on participation from being born in a non-English speaking country is overestimated in ‘traditional’ models (which do not include skills). It is the lower literacy and numeracy skills that people from a non-English speaking background have that, in part, explains their lower participation. Most of the other explanatory variables were statistically significant, and of the expected sign. Being married and having at least one child aged 0–4 or 5–14 had a negative effect on female participation. Mothers are more likely to spend time out of the labour force to care for younger children rather than older children, because looking after younger children is more time-intensive (Birch 2005). Recent empirical research for Australia (Cai 2010) also supports this theory. High levels of physical and mental health both had a positive effect on participation, for both men and women, consistent with results from previous Commission research (Laplagne, Glover and Shomos 2007). 6.2 Wages model results In this section, results from the wages models are presented. As was done for the participation models, the effects of education in both wages models are presented first, before the focus turns to the effect of literacy and numeracy skills on wages. 3 Some countries included in this definition may be English speaking. However, the vast majority of countries are non-English speaking. 52 LITERACY ANDNUMERACY SKILLS & LABOUR MARKET Effects of education for different model specifications Marginal effects of educational attainment on wages are presented in table 6.2. Based on equation 3, it was found that improving educational attainment had a large, statistically significant effect on wages. For example, increasing education from year 11 or lower to a degree increased hourly wages by about 60 per cent. This is larger than other estimates in the literature, although the marginal effect from increasing education from year 11 or lower to year 12 or a diploma/certificate was much smaller (between 11 and 18 per cent). All education effects were statistically significant. The estimated marginal effects for educational attainment for equation 4 (controlling for skills) were lower than those that were obtained for equation 3 (table 6.2). This pattern is the same which occurred for the labour force participation model. The estimated marginal effects for education were reduced by about half for men, and by a lesser amount for women. The effect of increasing schooling to year 12 (relative to year 11 or lower) was not statistically significant in equation 4. That is, raising education from year 11 to year 12 is not predicted to have any effect on hourly wages (unless skills are also improved by undertaking that education). Table 6.2 Marginal effects of educationa on hourly wages in differentmodel structures Men Women Explanatory variable Education only (Equation 3) With skills (Equation 4) Education only (Equation 3) With skills (Equation 4) Degree 59.58*** 34.21*** 61.05*** 49.42*** Diploma/Cert 17.65*** 9.77*** 13.76*** 10.28** Year 12 15.35*** 5.18 10.97** 7.24 a Marginal effects measure the percentage increase in hourly wages from increasing education from year 11or lower to the education levels estimated. *** significant at 1 per cent, ** 5 per cent and * 10 per cent. Source : Table B.9.Therefore, like the participation model, wage models which only use education may overstate the direct effect of education on hourly wages. Some of the expected increase in hourly wages occurs because more highly educated people also have higher literacy and numeracy skills. Like the participation model above, ability bias might also affect the results presented for the wages models. A number of studies have attempted to address this MODELLING RESULTS 53issue. Data on twins has been used by Ashenfelter and Kreuger (1994) for the United States and Miller, Mulvey and Martin (1995) for Australia. Those studies ‘reveal that there is little evidence of upward bias in the typical OLS estimate of the return to education’ (Miller, Mulvey and Martin 1995, p. 597). This arises because any upward bias is largely offset by measurement error, which has a downward bias on results. More recently, Leigh and Ryan (2008) estimated returns to education using various natural experiment techniques to control for ability bias. Their returns to education were higher than from studies using twins, and the authors attribute this to having better measures of income and schooling. Their results suggest that about 10 to 40 per cent of the return to schooling in standard OLS regressions may be due to ability bias. Effects of literacy and numeracy skills on wages Equation 4 models the effects of both education, and literacy and numeracy skills, on wages. Marginal effects are presented in figure 6.2. Figure 6.2 Marginal effects of education and skills on wagesEducational attainment relative to year 11 or lower, literacy and numeracy skills relative to level 1 a-10 0 10 20 30 40 50 60 70 Year 12 Diploma or Certificate Degree or higher Level 2 Level 3 Level 4/5 Increase in wages (%) Men Women a Bars show the 95 per cent confidence interval for the marginal effects, which were calculated at the mean. If,for a given variable, the bars overlap, then those estimates are not statistically different at the 5 per cent level of confidence. If a bar reaches the horizontal axis, that marginal effect is not statistically significant at the 5 per cent level of confidence. Data source : Table B.9.54 LITERACY ANDNUMERACY SKILLS & LABOUR MARKET The following observations regarding the effect of improving functional literacy and numeracy skills on wages can be made: • Increasing skills from level 1 to level 2 or above had a positive and statisticallysignificant effect on wages, for both men and women. • Increasing skills has a larger impact on returns to wages for men compared withwomen. This is in contrast to the effect that skills had on the likelihood of participation for men and women. • The effect of increasing skills on wages varies more along the skill distributionfor men than it does for women. 4– For men, increasing skills from level 1 to level 3 increases wages by 32 per cent, (14 percentage points more than from increasing skills from level 1 to level 2). However, an increase in skills from level 1 to level 4 or 5 raises wages by 54 per cent (a difference of 22 percentage points compared with raising skills from level 1 to level 3). Furthermore, the increase in wages from increasing skills from level 1 to level 2 is significantly different than from increasing skills to level 4 or level 5. – For women, the additional increase in wages is roughly 10 per cent from increasing skills from level 1 to level 2, compared with increasing skills from level 1 to level 3. The additional increase from improving skills to level 4 or 5 (compared with level 3) is also about 10 per cent. Furthermore, there is no statistical difference from improving skills from level 1 to level 2 compared with increasing them to any other level. Results were robust to various model specifications (for example, when literacy and numeracy was estimated as a continuous variable). In a similar analysis using the ALLS data, Barrett (2009) considered how the returns to skills vary along different points of the wage distribution. He found that the return to skills is uniform across the wage distribution. Finnie and Meng (2007) found that not only do skills benefit individuals at the top and bottom ends of the labour market, but that the effect of literacy and numeracy skills on labour market success is just as important as education. ‘Indeed, in some cases, the effects of functional literacy appear to be substantially greater than the number of years of education’ (Finnie and Meng 2007, p. 10). Likewise, the model 4 Strictly speaking, the effect on wages from increasing skills from level 3 to level 4/5 is not the difference between the marginal effects of skill levels 3 and 4/5 presented in figure 6.2. That would require re-estimating the model with level 3 as the base skill level. However, alternative models, with different skill level bases, were also estimated for comparison and gave similar results to the differences in marginal effects between skill levels above. MODELLING RESULTS 55results above suggest that improving skills has a larger impact on wages than improving education, particularly for men. For men, increasing skills from level 1 to level 4/5 has a larger effect on wages than from increasing education from year 11 to any of the other higher levels of educational attainment modelled. Even smaller improvements in skills for men (from level 1 to 2) have twice the impact on wages than from increasing educational attainment from year 11 to year 12 or to a diploma/certificate (although differences are not statistically different from one another). For women, increasing educational attainment to a degree or higher (from year 11 or lower) had a larger effect than improving literacy and numeracy skills. This could reflect that education acts as a stronger signalling device (of motivation or expectations at work) for women, compared with men. Other model results Potential labour market experience was included as a control variable in the wages equations. The results for equation 3 show that additional years of experience increase hourly wages, but at a decreasing rate (see appendix B for results). The magnitude of the effect of the experience variables was largely unaffected by including the skills variable (in equation 4), consistent with other results for Australia (Barrett 2009) and results for Canada (Green and Riddell 2002). This indicates that work experience might not improve literacy and numeracy skills. Descriptive analysis in chapters 3 and 4 suggested that literacy and numeracy skills might deteriorate once a person exits the workforce. Therefore, it may be the case that literacy and numeracy skills are developed prior to entering the workforce, but are maintained (and not enhanced) by using them in the workplace. They may deteriorate after leaving work, or may deteriorate due to other factors. This would be a useful area to explore in future research. Being born in a non-English speaking country was estimated to have a negative impact on wages. However, as in the participation model, once literacy and numeracy skills were controlled for, the negative effect was lessened (by about 25–50 per cent, depending on sex). Again, this highlights that human capital models which do not explicitly control for skills overstate the effect of being born in a non- English speaking country –– some of the effect occurs because this group has lower (English) literacy and numeracy skills. Most other explanatory variables are of the expected sign. Of those that are statistically significant, better mental or physical health, residing in the city, and being married (for men only) had a positive impact on hourly wage rates. 56 LITERACY ANDNUMERACY SKILLS & LABOUR MARKET Working part-time had a negative impact on wages of men and a positive impact for women, but was not statistically significant in either case. In contrast, a recent study of the Australian labour market showed that there was a wage premium from working part-time for both men and women (Booth and Wood 2008). 6.3 Summary of modelling results The econometric modelling results in this chapter have highlighted that improving functional literacy and numeracy skills has a large and statistically significant effect on labour force participation and hourly wages. The estimated benefits of education, after controlling for functional skills, were reduced but still significant. Thus, education develops other skills used in the workplace, and may act as a signal to employers that people with higher education have higher human capital. The above findings suggest that both educational qualifications and functional skills are valued in the labour force. The modelling did not formally estimate the impact of factors likely to affect functional skills. Green and Riddell (2001) estimated a joint model of skills, education and wages. They found education to be a strong factor explaining literacy and numeracy skills. However, formal education is usually undertaken prior to entering the workforce. Although education is likely to improve younger persons’ skills, people who are older and already working can also improve their functional skills. Understanding the determinants of a person’s literacy and numeracy skills, and how they can be improved (or maintained) at different stages of the life cycle, would be a good area for further research. The above analysis indicates that work experience might not improve functional literacy and numeracy skills. However, only a crude measure of work experience was used. The ALLS also has information on how often a person uses various skills in the workplace, and at home. Identifying whether using skills at work improves functional skills would be a good first step in understanding ways to improve the skills of older workers. CONCLUDING REMARKS 57 7 Concluding remarks In this paper, the links between literacy and numeracy skills and labour market outcomes were examined using recent Australian data. The motivation for the project has arisen from growing policy interest on the impact that literacy and numeracy skills have on key labour market outcomes. As mentioned in chapter 1, governments are committed to improving literacy and numeracy outcomes of the population, as this component of human capital is seen as crucial to raising productivity and participation. A summary of the key findings from the empirical analysis in this paper and how they can be used by policy makers is presented below. Areas for further research are also mentioned. 7.1 Summary of findings A profile of Australian’s functional literacy and numeracy skills in 2006 showed that skills typically: • decrease with age• are higher for more educated people• are lower for people born in a non-English speaking country.Skills were also shown to be important for labour market outcomes –– people with higher skills are more likely to - * participate in the labour force, * be employed in higher-skilled occupations, and * earn more, compared to people with lower skills. Econometric models were used to formally estimate the effect of functional literacy and numeracy skills on labour force participation and on hourly wages (which is an indicator of productivity). Modelling results should be used with caution. There may be unobserved characteristics which influence education and skills. People with greater motivation, potential or innate ability are more likely to undertake education, meaning that the effects of education might be overstated. Although the addition of the skill variable used in this paper might capture more accurately people’s skills (and other unobserved factors that education does not), it might not capture motivation or innate ability. If that were the case, there may be some upward bias in the results meaning that they should be regarded as an upper estimate of the benefits from improving literacy and numeracy skills on labour market outcomes. Notwithstanding those limitations, the qualitative conclusions from this research are likely to remain unchanged. Model results showed that education has a positive effect on labour market participation and wages. Education is likely to improve a person’s human capital, of which literacy and numeracy is one component. Once literacy and numeracy skills were controlled for, the effect of greater education on labour market outcomes was reduced, but it was still positive for most levels of attainment. This suggests that schooling develops skills other than functional literacy and numeracy, which are also rewarded in the labour market. Such skills may be vocational or job-specific. Increasing literacy and numeracy skills had a positive, statistically significant effect on both labour force participation and hourly wages. Thus, from a policy perspective, if people’s literacy and numeracy skills can be improved, then they will tend to achieve better labour market outcomes. As stated above, a person’s innate ability or motivation could affect his or her skill development. Thus, in practice, it might be difficult for a person with low literacy and numeracy to move to the highest skill level. Nevertheless, it is possible to increase the literacy and numeracy skills for the population as a whole. Theory, and analysis of the data, both suggest that education is one factor likely to affect skills. However, the analysis also showed that education and skills are not perfectly correlated. Other studies have found ‘the development and maintenance of cognitive skills is more complex than simply attending school or achieving a certificate of completion, and that education does not “fix” skill levels for life’ (Statistics Canada and OECD 2005, p. 60). Modelling results supported this view, showing that, even after controlling for educational attainment, increasing people’s skills will lead to higher wages and increased labour force participation. Therefore, understanding factors other than education which affect literacy and numeracy is of importance, and could be an area for further research. Using Canadian data, Willms and Murray (2007) found that people’s engagement in general literacy activities at work and at home have a stronger influence on skill development, compared with engagement in technical literacy practices at work.Other findings may also be of interest. For example, the effect of literacy and numeracy skills was different for men and women –– improving skills had a larger impact on participation for women than for men, but had a larger impact on hourly wage rates for men compared with women. Returns to skills also varied slightly along the distribution of lower and higher skilled workers. Raising the skills of lower-skilled people had a larger effect on increasing participation, compared with further improving high-skilled workers’ ability. Compared with raising educational attainment, most of the results showed that there was a larger payoff to labour market outcomes from improving skills. Finally, an important finding from the research was that people born in a non-English speaking country were much more likely to have lower functional skills than people born in Australia or a main English speaking country. This was the case regardless of a person’s educational attainment. Thus, improving language proficiency is paramount to enhancing the functional skills and, in turn, the labour market outcomes for that group. The empirical results support the findings of previous Commission research on migration, which found that ‘English language proficiency is significantly related to migrant labour market success and performance’ (PC 2006b, p. 172). 7.2 Future research areas Modelling results highlighted that education and functional literacy and numeracy skills have a positive effect on labour force participation and on wages. Estimates were based on standard econometric models often used in the literature, but they could be further refined using more sophisticated techniques. Although the qualitative conclusions are likely to remain unchanged, further research could be useful for policy makers if they wanted a more precise estimate of the effect of literacy and numeracy skills (and education) on labour market outcomes. There are many different model specifications that could be used. Some of these are mentioned below. 1. Hours worked. The effect of skills on participation could be estimated using ‘hours worked’ as the dependent variable instead of participation. Alternatively, a multinomial logit could be used to model participation (that is, the states of labour force status could be expanded to include people unemployed, working part-time, or working full-time). 2. Simultaneous equations. In the descriptive analysis, there was some evidence that people who are out of the labour force might experience skill deterioration. If participation does affect skills, then there is reverse causality. To account for this, a simultaneous equations model could be estimated with participation and literacy and numeracy skills jointly estimated. Using this model would help shed light on the direction of causality regarding skills and participation for people in the workforce nearing retirement age, which is likely to be of policy interest in the future. 3. Three-stage least squares. Literacy and numeracy skills are influenced by many factors, including education, engagement in reading and writing activities at work or home, English speaking background and parents’ education levels. Models could be estimated to examine which factors are more important for skill development. For example, Green and Riddell (2001) used a three-stage least squares model to jointly estimate wages, education and skills for Canada. Understanding the factors affecting literacy and numeracy skills, and how those skills can be improved at different stages of the life cycle would also be important. Thus the modelling could be done for different age groups. The econometric models in this paper can also be used to examine other links between literacy and numeracy skills and labour market outcomes. For example, separate marginal effects were estimated for increasing educational attainment and literacy and numeracy skills. These marginal effects are interpreted as the effect of changing one variable, holding all others constant. For example, the estimated marginal effect of improving education assumes that a person’s skill level is held constant. In practice, greater educational attainment is associated with higher skills (chapter 3). Therefore, a more realistic estimate of improving educational attainment for a person with relatively low education and low literacy and numeracy skills might consider the impact of improving both education and literacy andnumeracy. This could be incorporated with an interactive term for literacy and numeracy skills and education. Finally, although the focus of this report was to look at overall functional literacyand numeracy, the skill variable could be replaced and the effects of different types of literacy or numeracy could be estimated in isolation. Using data for the United States, Dougherty (2003) found that the effect of numeracy on earnings is much larger than that of literacy. A Descriptive statistics This appendix lists the variables used in the econometric models. The sample was restricted to 25–64 year old persons. Table A.1 contains a description of all the variables, and their means and standard errors. Table A.1 Variable definition and descriptive statisticsVariable Description Mean Std. Error Labour force 1 if in labour force, 0 otherwise 0.7728 Log wage Log of hourly wage rate x 100 234.3692 1.8906 Degree or higher 1 if degree or higher, 0 otherwise 0.2411 Diploma/certificate 1 if diploma/certificate, 0 otherwise 0.2743 Year 12 1 if year 12, 0 otherwise 0.1347 Skill level 2 1 if skill level 2, 0 otherwise 0.2849 Skill level 3 1 if skill level 3, 0 otherwise 0.3991 Skill level 4/5 1 if skill level 4/5, 0 otherwise 0.1695 Lives in city 1 if lives in city, 0 otherwise 0.5895 Married 1 if married, 0 otherwise 0.6122 Child 0–4 1 if child aged 0–4, 0 otherwise 0.1602 Child 5–14 1 if child aged 5–14, 0 otherwise 0.2672 Child 15–24 1 if child aged 15–24, 0 otherwise 0.0878 Age Age (years) 44.1943 0.1345 Age squared Age squared/100 20.7588 0.1205 Age cubed Age cubed/10 000 10.2670 0.0851 Experience Potential work experience (years) 26.3904 0.1490 Experience squared Potential work experience squared 8.4703 0.0827 Physical health SF12 physical health score (1–100) 49.8385 0.1175 Mental health SF12 mental health score (1–100) 50.6485 0.1165 Pension recipient 1 if receives any pension excluding disability and Department of Veteran Affairs (DVA) service pension, 0 otherwise 0.0102 Part-time 1 if works part-time, 0 otherwise 0.2127 COB – English speaking (not Aus) 1 if born in English speaking country (not Australia), 0 otherwise 0.1239 COB – other 1 if born in non-English speaking country, 0 otherwise 0.1531 Number of observations 6785 Source : Productivity Commission estimates based on the ALLS (2006).ESTIMATION OUTPUT 63B Estimation output This appendix contains output from all of the models estimated, including those models presented in chapter 6. As explained in chapter 5, each model was estimated separately for men and women, with the sample population being 25–64 year old persons. B.1 Labour force participation model Equations 1 and 2 (presented in section 6.1) were estimated using a probit model of labour force participation. The two states are either being in the labour force (employed or unemployed) or not in the labour force. Models were estimated with two specifications for functional literacy and numeracy skills. In the first instance, discrete skill levels were first estimated (results using this approach were presented in chapter 6). An alternative specification, with the continuous test score, was also used. Selected output from both of these models is presented below. Participation model results with skill levels The probit labour force participation model results for equations 1 and 2 are presented for men and women in tables B.1 and B.2 respectively. Results include coefficients and goodness of fit measures. Tables B.1 and B.2 also contain the associated marginal effects for key variables of interest. Marginal effects for all models were calculated at the mean (using the ‘mfx’ command in Stata). This method was chosen, rather than calculating the average marginal effect, because that command is not available in the version of Stata run through RADL. In either case, previous literature does not indicate any strong preference for choosing a particular method when estimating marginal effects. Table B.1 Participation model results for men, skill levelsVariable Equation 1 Equation 2 Log likelihood -863.6 -854.4 Pseudo R squared 0.2979 0.3054 Number of observations 3154 3154 Coefficients LitNum Skill level 2 – 0.2934*** LitNum Skill level 3 – 0.3575*** LitNum Skill level 4 and 5 – 0.5730*** Degree or higher 0.4397*** 0.2195* Diploma/Certificate 0.3118*** 0.2239*** Year 12 0.1188 -0.0010 Age 0.1898*** 0.1858*** Age squared -0.2503*** -0.2452*** Married 0.5010*** 0.4780*** Child 0–4 -0.0489 -0.0522 Child 5–14 -0.1365 -0.1327 Child 15–24 0.3619** 0.3527** Lives in city -0.0285 -0.0285 COB – English speaking (not Aus) 0.1792* 0.1424 COB – Other -0.0406 0.0671 Physical health 0.0420*** 0.0406*** Mental health 0.0214*** 0.0210*** Constant -5.4808*** -5.5340*** Marginal effects ppt ppt LitNum Skill level 2 – 3.69*** LitNum Skill level 3 – 4.67*** LitNum Skill level 4 and 5 – 6.16*** Degree or higher 5.20*** 2.78** Diploma/Certificate 4.07*** 2.93*** Year 12 1.56 -0.01 COB – English speaking (not Aus) 2.28* 1.82 COB – Other -0.58 0.89 *** significant at 1 per cent, ** 5 per cent and * 10 per cent. Source : Productivity Commission estimates based on the ALLS (2006).ESTIMATION OUTPUT 65Table B.2 Participation model results for women, skill levelsVariable Equation 1 Equation 2 Log likelihood -1755.0 -1732.9 Pseudo R squared 0.1803 0.1906 Number of observations 3631 3631 Coefficients LitNum Skill level 2 0.3744*** LitNum Skill level 3 0.5030*** LitNum Skill level 4 and 5 0.5743*** Degree or higher 0.7012*** 0.5284*** Diploma/Certificate 0.4609*** 0.3637*** Year 12 0.2796*** 0.1901** Age -0.3115** -0.3093** Age squared 0.9027*** 0.8980*** Age cubed a -0.8361*** -0.8305***Married -0.0752 -0.0921* Child 0–4 -0.5852*** -0.6051*** Child 5–14 -0.2406*** -0.2435*** Child 15–24 0.0178 0.0159 Lives in city -0.0349 -0.0223 COB – English speaking (not Aus) 0.0952 0.0985 COB – Other -0.3028*** -0.1579** Physical health 0.0306*** 0.0290*** Mental health 0.0154*** 0.0142*** Constant 1.9685 1.7111 Marginal effects ppt ppt LitNum Skill level 2 11.03*** LitNum Skill level 3 15.17*** LitNum Skill level 4 and 5 15.25*** Degree or higher 19.11*** 14.90*** Diploma/Certificate 13.08*** 10.53*** Year 12 8.13*** 5.65*** COB – English speaking (not Aus) 2.91 3.00 COB – Other -10.12*** -5.12** a A cubed age term was used for females, because it gave a better fit to the female age profile compared withonly using a squared term. *** significant at 1 per cent, ** 5 per cent and * 10 per cent. Source : Productivity Commission estimates based on the ALLS (2006).Participation model results with continuous skills variable The probit labour force participation model was also estimated using the continuous skills variable (test score 1–500) rather than with skill levels (1, 2, 3 and 4/5). Other variables used in estimation remained unchanged. Selected marginal effects for equation 2 with the continuous skills variable are presented for men and women in table B.3. The results confirm that higher literacy and numeracy has a positive effect on participation. The effect is larger for women (about three times greater than the effect for men, broadly in line with results using skill levels). The marginal effect of other variables of interest (education and country of birth) are also very similar to those results obtained with models using skill levels (those results are reported under equation 2 in tables B.1 and B.2 for men and women, respectively). Table B.3 Participation model results, continuous skills variableEquation 2 Variable Men Women Log likelihood -853.0 -1729.35 Pseudo R squared 0.3065 0.1922 Number of observations 3154 3631 Marginal effects ppt ppt Literacy/Numeracy score a 0.05*** 0.13***Degree or higher 2.40* 13.24*** Diploma/Certificate 2.69** 10.00*** Year 12 -0.30 5.12** COB – English speaking (not Aus) 1.82 2.97 COB – Other 1.29 -3.35 a The marginal effect for literacy/numeracy represents the increase in probability of labour force participationfor an additional one point in a person’s literacy/numeracy test score (which can be between 1 and 500). *** significant at 1 per cent, ** 5 per cent and * 10 per cent. Source : Productivity Commission estimates based on the ALLS (2006).B.2 Wages model results Wages models for equations 3 and 4 were estimated using standard OLS and with a Heckman selection model. Results from both of those models are reported below. The dependent variable is the natural logarithm of the hourly wage rate. For comparison, wages model results using a continuous skills variable are also presented at the end of this section. ESTIMATION OUTPUT 67OLS hourly wages model results Wages model results using OLS (for employed persons only) are reported for men and women in tables B.4 and B.5 respectively. Table B.4 OLS wages model results for menVariable Equation 3 Equation 4 Adjusted R squared 0.0842 0.1079 Number of observations 2407 2407 Coefficients Lives in city 0.0850*** 0.0844*** Married 0.1211*** 0.1021*** Experience 0.0215*** 0.0195*** Experience squared -0.0338*** -0.0278*** Degree or higher 0.4685*** 0.2952*** Diploma or certificate 0.1630*** 0.0936*** Year 12 0.1430** 0.0506 LitNum Skill level 2 0.1648*** LitNum Skill level 3 0.2786*** LitNum Skill level 4 and 5 0.4334*** Physical health 0.0041** 0.0033* Mental health 0.0015 0.0016 COB – English speaking (not Aus) 0.0254 0.0202 COB – Other -0.1552*** -0.0698* Works part-time -0.0693 -0.0620 Constant 2.3439*** 2.2139*** *** significant at 1 per cent, ** 5 per cent and * 10 per cent. Source : Productivity Commission estimates based on the ALLS (2006).Table B.5 OLS wages model results for womenVariable Equation 3 Equation 4 Adjusted R squared 0.0926 0.1015 Number of observations 2244 2244 Coefficients Lives in city 0.0604** 0.0597** Married 0.0553* 0.0473* Experience 0.0112** 0.0099* Experience squared -0.0158 -0.0111 Degree or higher 0.4783*** 0.4030*** Diploma or certificate 0.1300*** 0.0988** Year 12 0.1059** 0.0713 LitNum Skill level 2 0.1295** LitNum Skill level 3 0.2086*** LitNum Skill level 4 and 5 0.2999*** Physical health 0.0072*** 0.0066*** Mental health 0.0036** 0.0033** COB – English speaking (not Aus) 0.0410 0.0427 COB – Other -0.2221*** -0.1626*** Works part-time 0.0213 0.0250 Constant 2.1140*** 2.0077*** *** significant at 1 per cent, ** 5 per cent and * 10 per cent. Source : Productivity Commission estimates based on the ALLS (2006).Marginal effects Marginal effects in an OLS model are equivalent to the corresponding coefficients. However, the dependent variable used in the wages model was the logarithm of the hourly wage. The marginal effects had to be converted to obtain a percentage growth rate in wages from a percentage change in the explanatory variable. Thornton and Inness (1989) show that the estimated marginal effect when the dependent variable is in logarithmic form needs to be converted with the following formula: %Δ Wages =X. eβ – 1where β is the estimated marginal effect, and X is the unit change in the dependentvariable. For a binary variable, X is 1. Therefore, the education and skills marginaleffects in tables B.4 and B.5 were converted using the following formula: %Δ Wages =eβ – 1The marginal effects for the OLS wages models (for both men and women) are presented in table B.6. ESTIMATION OUTPUT 69Table B.6 Marginal effects of selected variables in OLS wages modelsVariable Equation 3 (Education only) Equation 4 (With skills) Men Women Men Women Degree or higher 59.75*** 61.34*** 34.34 *** 49.63*** Diploma or certificate 17.71*** 13.88*** 9.81 *** 10.39** Year 12 15.37*** 11.17** 5.19 7.39 Skill level 2 17.92 *** 13.82** Skill level 3 32.13 *** 23.19*** Skill level 4/5 54.25 *** 34.97*** COB – English speaking (not Aus) 2.57 4.18 2.04 4.36 COB – Other -14.38*** -19.92*** -6.74 * -15.01*** *** significant at 1 per cent, ** 5 per cent and * 10 per cent. Source : Productivity Commission estimates based on the ALLS (2006).Heckman model results In this section, a description of the Heckman model that was used to estimate the wages models is provided below. Following that, estimation results for the wages models (outlined in section 6.2) are presented. Heckman model specification A formal representation of the Heckman model is presented below. The following selection equation is first estimated: Prob(L = 1 | Z) = Φ(Zγ) where: L = 1 if in labour force, and 0 otherwise Z is a vector of explanatory variables, and γ includes parameters to be estimated. Z includes the education variables, skill variables (for equation 4) and other demographic variables (those estimated for the labour force participation models). A second (wage) equation, is then estimated: w * = Xβ + u1where: w* is a wage offer, which is only observed if a respondent is working. The conditional wage, given a person works is then: E[ w | X, L = 1] = Xβ + E[u | X, L = 1]E[ w | X, L = 1] = Xβ + ρσuλ(Zγ)where: ρ = correlation between error terms in the first and second equationsσ u = standard deviation of uλ = inverse mills ratio.The above equation can be rewritten as: E[ w | X, L = 1] = Xβ + cλ(Zγ)where: c = ρσuThe value of c (the coefficient of λ), can be tested to see if it is statistically differentfrom zero. If it is, there is a ‘selection effect’ present. By controlling for this, wage model estimates are unbiased. However, there was no statistically significant effect (see below), meaning that sample selection bias is not a problem according to the model results. A problem in estimating Heckman models like the above is finding relevant ‘instruments’ –– variables that affect participation, but which do not influence wages. The variables specifically used as instruments (that is, in the participation equation only) were: having a child aged 0–4; child aged 5–14; child aged 15–24; age (including squared and cubed terms). Estimation output The coefficient estimates for equations 3 and 4 are presented in tables B.7 and B.8 for men and women respectively. These results include explanatory variables used in both the selection and wage equations. ESTIMATION OUTPUT 71Table B.7 Heckman wages model results for menVariable Equation 3 Equation 4 Selection equation Lives in city -0.0463 -0.0467 Married 0.5433*** 0.5219*** Age 0.1744*** 0.1683*** Age squared -0.2304*** -0.2230*** Degree or higher 0.5022*** 0.2611** Diploma or certificate 0.4117*** 0.3148*** Year 12 0.2124** 0.0824 LitNum Skill level 2 0.3020*** LitNum Skill level 3 0.3601*** LitNum Skill level 4 and 5 0.6250*** Physical health 0.0404*** 0.0388*** Mental health 0.0232*** 0.0227*** COB – English speaking (not Aus) 0.1625 0.1351 COB – Other -0.1779* -0.0594 Child 0–4 -0.0106 -0.0119 Child 5–14 -0.1200 -0.1181 Child 15–24 0.2526* 0.2359 Constant -5.5131*** -5.5195*** Wage equation Lives in city 0.0847*** 0.0841*** Married 0.1249*** 0.1056*** Experience 0.0220*** 0.0200*** Experience squared -0.0352*** -0.0291*** Degree or higher 0.4706*** 0.2960*** Diploma or certificate 0.1654*** 0.0953*** Year 12 0.1443*** 0.0511 LitNum Skill level 2 0.1673*** LitNum Skill level 3 0.2813*** LitNum Skill level 4 and 5 0.4371*** Physical health 0.0045** 0.0036* Mental health 0.0017 0.0017 COB – English speaking (not Aus) 0.0261 0.0208 COB – Other -0.1563*** -0.0702* Works part-time -0.0696 -0.0623 Constant 2.3040*** 2.1745*** Lambda 0.0238 2.3155 Log likelihood -3322.4 -3278.1 *** significant at 1 per cent, ** 5 per cent and * 10 per cent. Source : Productivity Commission estimates based on the ALLS (2006).Table B.8 Heckman wages model results for womenVariable Equation 3 Equation 4 Selection equation Lives in city -0.0061 0.0033 Married 0.0110 -0.0084 Age -0.3467*** -0.3486*** Age squared 0.9635*** 0.9678*** Age cubed -0.8647*** -0.8645*** Degree or higher 0.7765*** 0.5735*** Diploma or certificate 0.4627*** 0.3508*** Year 12 0.3172*** 0.2167*** LitNum Skill level 2 0.3886*** LitNum Skill level 3 0.5652*** LitNum Skill level 4 and 5 0.6704*** Physical health 0.0294*** 0.0276*** Mental health 0.0165*** 0.0151*** COB – English speaking (not Aus) 0.0959 0.0998 COB – Other -0.3925*** -0.2253*** Child 0–4 -0.6031*** -0.6273*** Child 5–14 -0.2548*** -0.2595*** Child 15–24 -0.0048 -0.0058 Constant 2.3188 2.1064 Wage equation Lives in city 0.0610** 0.0603** Married 0.0534* 0.0453 Experience 0.0125** 0.0110** Experience squared -0.0189* -0.0136 Degree or higher 0.4970*** 0.4148*** Diploma or certificate 0.1416*** 0.1061*** Year 12 0.1129** 0.0751 LitNum Skill level 2 0.1396** LitNum Skill level 3 0.2223*** LitNum Skill level 4 and 5 0.3148*** Physical health 0.0080*** 0.0072*** Mental health 0.0041** 0.0036** COB – English speaking (not Aus) 0.0427 0.0443 COB – Other -0.2330*** -0.1681*** Works part-time 0.0177 0.0219 Constant 2.0074*** 1.9118*** Lambda 0.0579 0.0489 Log likelihood -3942.6 -3903.4 *** significant at 1 per cent, ** 5 per cent and * 10 per cent. Source : Productivity Commission estimates based on the ALLS (2006).ESTIMATION OUTPUT 73Marginal effects Marginal effects for the education and skills variables were calculated using the same Stata command used for the models of participation (described above). This estimate had to be converted to obtain percentage change in the same way the OLS wages model estimates were converted. Marginal effects of skills and educational attainment are presented in table B.9. Table B.9 Marginal effects of selected variables in Heckman modelsVariable Equation 3 (Education only) Equation 4 (With skills) Men Women Men Women Degree or higher 59.58*** 61.05*** 34.21 *** 49.42*** Diploma or certificate 17.65*** 13.76*** 9.77 *** 10.28** Year 12 15.35*** 10.97** 5.18 7.24 Skill level 2 17.97 *** 13.92** Skill level 3 32.16 *** 23.20*** Skill level 4/5 54.26 *** 35.02*** COB – English speaking (not Aus) 2.53 4.08 2.01 4.27 COB – Other -14.35*** -19.79*** -6.74 * -14.98*** *** significant at 1 per cent, ** 5 per cent and * 10 per cent. Source : Productivity Commission estimates based on the ALLS (2006).Wages model with continuous skills variable The wages models were also estimated with the continuous test score variable, instead of the skill level variables. Qualitative results were unchanged. For information, the marginal effects from the OLS models estimated with the continuous variable, or alternatively the skill level variable, are presented in table B.10. (Results for the Heckman model with the continuous variable are not reproduced here, but were similar to those of the OLS model). The marginal effect of the literacy and numeracy test score variable for men is about 1.5 times the magnitude for women, in line with results from models which use the skills level variables. Table B.10 Marginal effects for wages models using different specifications for the skill variable in equation 4OLS regression, employed persons Men Women Variable Skill level Test score Skill level Test score Degree or higher 34.21*** 32.27*** 49.42*** 47.80*** Diploma or certificate 9.77*** 8.46** 10.28** 9.62** Year 12 5.18 4.20 7.24 6.66 Literacy/numeracy test score 0.27 *** 0.19 *** Skill level 2 17.97*** 13.92** Skill level 3 32.16*** 23.20*** Skill level 4/5 54.26*** 35.02*** COB – English speaking (not Aus) 2.01 1.93 4.27 4.53 COB – Other -6.74* -4.38 -14.98*** -14.11*** Source : Productivity Commission estimates based on the ALLS (2006). |
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