DPRIETI Discussion Paper Series 12-E-009

Postgraduate Education and Human Capital Productivity
in Japan
MORIKAWA Masayuki
RIETI

The Research Institute of Economy, Trade and Industry

http://www.rieti.go.jp/en/

RIETI Discussion Paper Series 12-E-009
February 2012

Postgraduate Education and Human Capital Productivity in Japan
MORIKAWA Masayuki
RIETI

Abstract
In advanced countries, including Japan, the number of workers with postgraduate degrees isincreasing. These highly educated workers are important contributors to innovation. This
paper, using published data from the Employment Status Survey, estimates standard wage
functions to investigate the effects of postgraduate degree on productivity and the rate of
return on postgraduate education. According to the analysis, wage premium forpostgraduates relative to undergraduates is about 20% in Japan, which is comparable to thefigures found in the United States and the United Kingdom. The premium is larger for
female employees. Wage reduction after age 60 is smaller, and retirement age is higher for
workers with postgraduate education. Considering the trend toward advanced technology
and the growing demand for human capital, postgraduate education is becoming importantto vitalize the Japanese economy. At the same time, expansion of postgraduate education
may contribute to narrowing the wage gap between male and female workers andincreasing labor force participation of elderly people.

Keywords: postgraduate education, wage premium, wage function
JEL classifications：I20, J31
RIETI Discussion Papers Series aims at widely disseminating research results in the form ofprofessional papers, thereby stimulating lively discussion. The views expressed in the papers aresolely those of the author(s), and do not represent those of the Research Institute of Economy, Tradeand Industry.


The author would like to thank Reiko Aoki, Masahisa Fujita, Daiji Kawaguchi, Kotaro Tsuru,
Kazuo Yamaguchi and the seminar participants at RIETI for their helpful comments andsuggestions.

-1-1. Introduction

In advanced countries, including Japan, the number of workers with postgraduate degrees isincreasing rapidly. These highly educated workers are important contributors to innovation.
However, the “highly educated working poor” is a group that is often reported by the mass
media and is regarded as a social problem in Japan. Considering the trend toward aknowledge-based economy, the effect of investments in advanced education, especially
postgraduate education, on human capital productivity is an important policy interest.
According to the School Basic Survey, conducted annually by the Ministry of Education,
Culture, Sports, Science and Technology (MEXT), the numbers of new postgraduates with
MA and Ph.D. degrees who obtained jobs in 2011 were about 54,000 and 10,000, respectively(see Table 1), an increase of more than 3% per annum during the last ten years. This growthrate is higher than the figure for undergraduates (0.9% per annum). A large number of
postgraduates obtained jobs in manufacturing, information and communications, and medical
service industries (see Table 2), which are characterized as industries of rapid technologicalprogress. Professional and engineering jobs are the dominant occupations for postgraduates.
However, a large number of people with Ph.D. degrees obtained jobs in the education services
sector, indicating that these people are working as professors or teachers. According to the
Employment Status Survey (Ministry of Internal Affairs and Communications), in 2007, theshare of workers with postgraduate educations to the total number of workers was only 2.0%,
but this share is higher for younger cohorts. For example, among workers aged 25 to 39, theshare of postgraduate education to total workers is 3.3%, and the share of workers witheducation higher than a bachelor’s degree exceeds 10% (see Table 3, column (5)).
Workers with postgraduate degrees are important contributors to innovation. According to
the Inventor Survey, conducted by the Research Institute of Economy, Trade and Industry(RIETI), 28.6% of the important patents and 12.9% of the triadic patents (patents filed inJapan and the EPO and granted by the USPTO) are filed by Ph.D. holders (Nagaoka andTsukada, 2007; Nagaoka, 2010). Although these figures are lower than the comparable
figures in the U.S. and Europe, it should be noted that the number of Ph.D. holders in Japan
is small. Jones (2009, 2010) noted that the educational burden on recent cohorts of-2-

innovators has increased due to the increase in the stock of knowledge, and the age at firstinvention has been increasing over time. To produce significant innovations, a significant
investment in higher education is required.
An estimation of the effect of postgraduate education is lacking because official labor
statistics in Japan did not differentiate between undergraduates and postgraduates until very
recently. However, this situation is gradually changing. The Basic Survey on Wage Structure(Ministry of Health, Labour and Welfare), which examines starting salaries, made a
distinction between postgraduate and undergraduate education in its 2005 Survey. According
to the 2011 results, the average starting wages of postgraduates are higher than the wages ofundergraduates by 14% for male employees and 20% for female employees. The
Employment Status Survey, used in this paper, introduced a questionnaire distinguishingpostgraduates and undergraduates in its latest survey in 2007.
Based upon this background, this paper investigates the effects of postgraduate education
on workers’ productivity in Japan. Specifically, this paper estimates simple wage functions
by using published statistical data of the 2007 Employment Status Survey and calculates therate of return on the investment in postgraduate education. The contribution of this paper is
its focus on the effect of postgraduate education not only on the wages of working people,
but also on labor participation and its calculation of the rate of return by incorporating both
wages and labor participation rates.
The major results of the analysis can be summarized as follows.
(1) According to simple wage function estimations that use sex, age, education, andemployment status as explanatory variables, the wage premium for postgraduate workers
relative to undergraduate workers is approximately 20% in Japan, which is comparable tothe figures found in the United States and the United Kingdom.
(2) Among employees, the postgraduate wage premium is larger for female employees thanfor male employees.
(3) The postgraduate wage premium is very large for male self-employed individuals.
(4) The wage reduction after age 60 is smaller and the retirement age is higher for workers
with postgraduate educations. In other words, people with postgraduate educations earnhigher wages and remain in the labor market longer.
(5) The private rate of return on the investment in postgraduate education is 10% or more.

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The social rate of return, including the benefits from knowledge spillovers, may be muchhigher.

This paper is structured as follows. Section 2 briefly reviews the relevant studies on the
postgraduate wage premium. Section 3 explains the method of analysis and the data used inthis paper. Section 4 reports and interprets the results, and Section 5 concludes with policy
implications.

2. Literature review
There have been numerous studies on the returns of education. In advanced countries, theaverage estimate of the gross rate of return of a year of additional education ranges between
5% and 10% (see survey articles such as Card (1999, 2001); Blundell et al. (1999); Meghir
and Rivkin (2011)). In Japan, Kawaguchi (2011) conducted a comprehensive analysis of thewage structure and found that the rate of return for an additional education of a year for
highly educated workers was approximately 10% when their tenure was relatively short, but
the rates monotonically increased as the tenure increased. However, most previous studies
have not distinguished between undergraduate and postgraduate education.
Studies on the effect of postgraduate education on wages have been very limited, but there
are several exceptions in the U.S. and the UK. Jaeger and Page (1996), using the U.S.
Current Population Survey (CPS) data, found that postgraduate degrees are valued by thelabor market. Specifically, MA degree holders earn 5.5%-15.5% more and Ph.D. degree
holders earn 8.3%-10.3% more than holders of bachelor's degrees. By sex, the wage
premium of a postgraduate degree is larger for females than for males. Card’s (1999)
representative survey on the relationship between education and wages indicated that thewages of workers with MA and Ph.D. degrees were approximately 20% and 30% higher,
respectively, than were those of workers with undergraduate educations. Deere and Vesovic(2006) used data from the U.S. Census and found that the hourly wage for workers withpostgraduate educations was approximately 30% higher than the wage for workers with-4-

college educations in 2000. Song et al. (2008) used the U.S. scientist and engineer statistics
data system, collected by the NSF for 1993, and found that the sorting effect produced asubstantial downward bias in estimated returns on graduate education. Furthermore, theseauthors found that correcting for the sorting effect raised estimated annualized returns on amaster’s or doctoral degree from approximately 5% to 7.3% and 12.8%, respectively.
In the UK, Walker and Zhu (2011) used data from the Labour Force Surveys todemonstrate that males (females) with MA degrees earned 12% (17%) more than those with
undergraduate degrees and that males (females) with Ph.D. degrees earned 4% (7%) morethan those with MA degrees. It is interesting to note that the postgraduate wage premium islarger for females than for males.
Lindley and Machin (2011) analyzed the change in the number of workers with postgraduate
qualifications and their relative wages in the U.S. and the UK. They reported that in the U.S.,
the postgraduate/undergraduate wage differential rose from zero in 1963 to a gap of 0.28 log
points by 2009, whereas in the UK, the postgraduate/undergraduate wage gap increased from0.05 log points in 1996 to 0.12 log points in 2009. These authors argued that postgraduates
and undergraduate workers were imperfect substitutes in production and that the principal
beneficiaries of technological change (the computer revolution) have been skilled workers
with postgraduate qualifications, not all graduates.
In Japan, to the best of our knowledge, the postgraduate wage premium has not beenstudied empirically. An exception is Shimizu and Higuchi’s (2008) study, which analyzed
MBA qualifications and wages using an original survey of MBA holders in Japan.
According to their analysis, MBA acquisition in foreign countries increased wages morethan 50%, but MBA acquisition in Japanese universities did not have a significant effect on
wages.
To summarize, in the U.S. and the UK, significant effects on wages due to postgraduate
education have been identified, and these effects have increased over time. These recent
studies suggest that it is important to distinguish between undergraduate and postgraduate
education in empirical analyses of the relationship between education and labor market
outcomes.

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3. Data and Methodology
As described in the introduction, the Employment Status Survey (Ministry of Internal
Affairs and Communications) introduced a revised questionnaire that distinguishedpostgraduates from undergraduates in the 2007 survey. The aim of the Employment Status
Survey is to obtain basic data on the actual conditions of the employment structure at bothnational and regional levels by surveying the labor force in Japan. The survey was conducted
every three years from 1956 to 1982 and every five years since 1982. The 2007 survey was
conducted on October 1, 2007 among household members 15 years or older, including
approximately 450,000 households and one million people. Survey items included sex, age,education, employment status, type of employment, industry, occupation, days worked peryear, regularity of work, working hours per week, and annual income earned in workers’
main jobs. Employee income is defined as the gross earnings, inclusive of tax, gained during
the previous year from wages, salaries, various allowances, and bonuses. The income ofself-employed workers is defined as revenue gained during the previous year from business,
namely gross sales less necessary associated expenses. Income from financial assets andearnings from side jobs are not included in the annual income for the survey. In this paper,“annual income” and “wages” are used interchangeably.
Most of the survey items are categorical variables. For example, age groups are
categorized in 5-year intervals: 15-19, 20-24, 25-29...75-79, 80-84, and 85 or older.
Educational attainment is grouped into 6 classes: 1) primary school or junior high school, 2)senior high school, 3) vocational school, 4) junior college, 5) college or university, and 6)
graduate school. Unfortunately, MA degrees and doctoral degrees are not treated separately.
Annual income is categorized into 15 classes: 1) less than 500,000 yen, 2) 500,000 to
990,000 yen, 3) 1 to 1.49 million yen, 4) 1.5 to 1.99 million yen, 5) 2 to 2.49 million yen ...
13) 9 to 9.99 million yen, 14) 10 to 14.99 million yen, and 15) 15 million yen or more.
In this paper, we use the cell-level data taken from the published tables of the 2007 survey
on the number of people engaged in work by age, employment status, type of employment,
annual income, sex, and education. The central values of the annual income classes are-6-

converted to logarithmic form and used in the analysis.1
Using this data set, first, we observe the unadjusted wages of postgraduate workers by sex
and employment types (all workers, regular employees, and self-employed).2 Then, we
estimate standard wage functions to explain the log annual income. Because we can use only
published cell-level data, the available explanatory variables are limited. Specifically, in
addition to education dummies, sex, age, and type of employment are used as explanatory
variables. In the Employment Status Survey, “regular employees” are defined as “persons
who are called ‘regular employees’ at their workplace.” Education and age groups are usedas dummy variables. Technically, educational attainment can be converted into years ofeducation, and age can be converted into a continuous variable by using the central value ofthe age classes. However, in Japan, Kawaguchi’s (2011) comprehensive study of the Japanesewage structure noted that educational attainment should be included as discrete dummy
variables rather than a single index of the years of education. Furthermore, that study
suggested that the discontinuity in the wage profile at age 60 due to mandatory retirement
should be considered when choosing model specifications.
Because the focus of this study is the differences between workers with postgraduate andundergraduate educations, undergraduate education is used as the reference group. As aresult, the estimated coefficient for the postgraduate education dummy is the postgraduate
wage premium relative to the undergraduate wage. For the age classes, ages 20-24 to ages
80-84 are used in the analysis, and the 20-24 age group is used as the reference group.
Regarding sex and employment type, male employees and regular employees are used as thereference groups. Specifically, a dummy for female employees and dummies for non-regular
employees and self-employed workers are used in the regressions. A weighted least square(WLS) estimation is employed in which the number of workers in each cell — 15 income
classes * sex * 13 age classes * 6 education categories * 3 employment types — is used as the1“Less than 500,000 yen” and “15 million yen or more” are treated as 500,000 yen and 15 million
yen, respectively. Because the share of “15 million yen or more” is relatively large among
postgraduate workers, the estimated postgraduate wage premium may understate the true premium.
2
Non-regular employees include part-time workers, temporary workers, temporary agency
workers, and contract employees. Persons engaged in work include the “executive of company or
corporation” and “family workers.” However, we do not include these types of workers in thisstudy because the annual income of these groups by sex, age, and education are not published.

-7-

weight. To summarize, the baseline equation to be estimated is expressed below (equation(1)). The average figures of the variables by workers with undergraduate and postgraduate
educations are shown in Table 4.

ln(w) = ß0 + ß1 female dummy + ß2 age dummies + ß3 education dummies+ ß4 employment type dummies ＋ ε(1)

Next, we observe the labor participation rates of people with postgraduate educations by
sex and age classes in comparison with people with only an undergraduate education. Then,
we calculate the discounted present value of lifetime earnings and the rate of return on
investment in postgraduate education by considering both the wages and the labor
participation rates by sex and age groups.

4. Observations and empirical results
According to the published statistics of the Employment Status Survey in 2007, theaverage annual income was 5,238,000 yen and 6,777,000 yen for workers with
undergraduate and postgraduate educations, respectively. Focusing only on regular
employees, the figures are 5,726,000 yen and 7,119,000 yen for undergraduate andpostgraduate educations, respectively, indicating that the average wage level of postgraduate
workers was 24.3% higher than the wage level of undergraduate workers. By sex, the wage
levels of postgraduate male and female workers were 21.9% and 36.6% higher than thecorresponding wages for workers with an undergraduate education (see Table 5). When thesample is limited to only regular employees, the figures are 18.9% for male employees and36.4% for female employees, indicating that the postgraduate wage premium is still larger
for female employees.
Table 6 presents the estimation results of the wage functions. The baseline result showsthat the postgraduate wage premium is 18.2% (log points), on average (column (1) of Table
6). Column (2) of the table shows the interaction term of postgraduate education with the-8-female dummy added as a right-side variable. The coefficient for the interaction term is
positive and highly significant, indicating a larger postgraduate wage premium for female
workers. Columns (3) and (4) show the results of separate estimations for male and female
employees. In this specification, the estimated postgraduate wage premium is 21.5% formale employees and 23.2% for female employees. These figures are larger than those incolumn (1), and the male-female differential is smaller than in column (2). The major reason
for these differences is that the effects of age on wages differ significantly by sex. That is,
the average age-wage profile for male and female workers is different in Japan because alarge number of females work part time and are often not within the seniority wage system.
However, the wage differential between male and female workers is smaller for those withpostgraduate educations than for those with undergraduate educations. This fact suggeststhat the increase in the number of female postgraduates with specialized skills may
contribute to narrowing the wage gap between male and female workers.
Table 7 shows the postgraduate wage premium estimated by type of employment. The
wage premium is very large for male self-employed workers. There are various types ofself-employment, from owners of traditional small shops to highly qualified specialists, suchas physicians and lawyers or entrepreneurs of innovative firms. Self-employment with apostgraduate education seems to be quite different from self-employment among those with
only an undergraduate education.
Next, we compare the age-wage profile of postgraduates and undergraduates based on the
regression results presented above. Figure 1 and Figure 2 show the wage profiles of regular
employees and male self-employed workers, respectively. When we examine the wage
profile of regular employees, undergraduate-degree workers’ wages drop abruptly just afterage 60, which is a well-known phenomenon in the Japanese labor market. In contrast,
interestingly, the drop in wages after age 60 among workers with postgraduate educations isvery small. Despite the policy efforts to extend the compulsory retirement age, mostJapanese firms have not extended the formal retirement age, but they re-employ elderly
workers at significantly reduced wages. However, the productivity level of workers withpostgraduate educations seems to be maintained, possibly because their high skills do notdepreciate rapidly and they actively engage in specialized jobs. The wage profiles of male-9-

self-employed workers also differ significantly between undergraduates and postgraduates.
The wages of self-employed workers with undergraduate educations differ with age,increasing slowly during their 30s and 40s and gradually decreasing after their 50s. In
contrast, the wages of self-employed workers with postgraduate qualifications increase
rapidly until age 50, and the level continues to be far higher than the wage level for workers
with only an undergraduate education. This difference is because a large number ofself-employed workers with postgraduate educations are highly skilled.
It may be argued that the slow decline in wages of postgraduates after age 60 may be a
result of the selection mechanism in which relatively low-wage workers tend to retire, leaving
only high-wage earners in the labor market. To verify this possibility, Figure 3 shows the labor
participation rates by age groups. 3 The labor participation rate of older people withpostgraduate educations is more than 10 percentage points higher than the rate for both males
and females with only undergraduate educations, and the average retirement age of people
with postgraduate educations is relatively high.4 In the case of individuals with MA degrees,
the average time for entering the labor market is 2 years later than for the undergraduates, but
the age of retirement is also more than 2 years later. Therefore, the lifetime working years are
longer for postgraduate workers than for those with only undergraduate degrees. This factsuggests that the intellectual skills and knowledge of postgraduate workers depreciate slowly.5
Based on these observations and estimation results, we now calculate the rate of return on
investment in postgraduate education. In calculating the discounted present value of lifetime
income, some assumptions should be made. First, postgraduate education is assumed to be
an MA course. This is a rather strong assumption, but the ratio of MA degrees to the total

3

In calculating the labor participation rates by age groups, individuals attending school are
included in the denominator.
4
Shimizutani and Oshio (2010) indicate that in Japan, the likelihood of exiting the labor force islower for highly educated older males, and educational attainment is not related to the work statusof females. However, the data used in their study do not distinguish between postgraduate andundergraduate education.
5
Another possibility is the better health status of highly educated people. The strong positive
relationship between education and health is a stylized empirical regularity (see, for example, Eideand Showalter (2011) and Cutler and Lleras-Muney (2012)). In Japan, an analysis using theJapanese Study of Aging and Retirement (JSTAR), conducted by the Research Institute of
Economy, Trade and Industry (RIETI), indicates a positive relationship between education andhealth among older people (Ichimura et al., 2009).

- 10 -

number of new postgraduates obtaining jobs has been approximately 84% in recent years (seeTable 1). Second, we assume the discount rate to be 3% per year.
Additional lifetime earnings produced by postgraduate education depend both on income
levels and labor participation rates throughout life. Therefore, we first calculate annual income
multiplied by labor participation rates by age groups to obtain the discounted present value ofthe lifetime income. According to this calculation, the lifetime earnings of male workers withpostgraduate educations are approximately 35 million yen (28.8%) higher than the lifetime
earnings of workers with only undergraduate educations (see Table 8). This difference is 28
million yen (50.3%) for female workers. With the assumption that annual school expenses andliving expenses are 3 million yen, the rate of return on investment in postgraduate education isapproximately 12% for men and about 10% for women (see Table 8, column (3)). In thiscalculation, the opportunity cost is set as the average first two years of income earned by new
undergraduate workers (2.78 million yen for men and 2.57 million yen for women). Thesefigures are conservative because the assumption of 3 million yen for annual school and living
expenses may be somewhat high.6 If we assume these annual expenses to be 1.5 million yen,
the estimated rate of return will be higher: 16% for men and 13% for women (Table 8 (4)).
These figures are the private rate of return on investment. The social rate of return may bemuch higher because knowledge and innovations generated by high-level human capital havepositive spillover effects.7

Several reservations should be noted in the analysis of this paper. First, we do not use
individual-level micro data, and we rely on cell-based published statistics from the
Employment Status Survey. As a result, we have limited control over individual workers’
characteristics. However, because the sample size is large, we believe that the estimatedpostgraduate wage premium using micro data does not differ significantly. Second, because
the income data from the survey is multiple-choice style and the share of “15 million yen or
6

In Japan, the annual cost of a private university for postgraduate education (science andengineering courses) is approximately 1.2 to 1.8 million yen in the first year and approximately 0.9
to 1.5 million yen in the second year. In the case of national universities, the figures areapproximately 0.8 million yen in the first year and approximately 0.5 million yen in the secondyear.
7See, for example, Moretti (2004) and Falck et al. (2011). In contrast, government support for
postgraduate education decreases the social rate of return relative to private returns.

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more” is relatively large among postgraduate workers, the postgraduate wage premium inthis study may be underestimated. However, the possibility of underestimation strengthens
the results of this paper because the wage premium and the rate of return on postgraduate
education are statistically and economically significant. Third, because the analysis in thispaper uses cross-sectional data for the single year of 2007, the existence of a postgraduate
wage premium does not necessarily imply a causal relationship. The observed wage
premium may result from 1) the effects of postgraduate education on upgraded humancapital, 2) the signal effect, and 3) the selection effect. The analysis in this paper does notdisentangle these competing explanations. Fourth, although the 2007 Employment Status
Survey is innovative in distinguishing between postgraduate and undergraduate educational
attainment, the differences between MA and Ph.D. degrees remains unclear. Finally, as
indicated by Cameiro and Lee (2011) in the U.S., due to the increase in the ratio of students
who continue to universities, the quality of average undergraduate students may bedeclining. As a result, the estimated postgraduate wage premium may reflect the relative
decline in the quality of workers with only an undergraduate education.

5. Conclusion

Using published data from the Employment Status Survey in 2007, this paper estimates
standard wage functions to investigate the effects of postgraduate qualifications on wages andcalculates the rate of return on postgraduate education.
The major results of the analysis can be summarized as follows.
(1) According to the WLS regressions, in which sex, age, education, and employment status
are used as explanatory variables, the wage premium for workers with postgraduate
degrees relative to those with undergraduate degrees is approximately 20% in Japan,
which is comparable to the figures found in the U.S. and the UK.
(2) The postgraduate wage premium is larger for female employees than for male employees.
(3) The postgraduate wage premium is very large for male self-employed workers.
(4) Wage reduction after age 60 is smaller and retirement age is higher for workers with a- 12 -

postgraduate education. In other words, people with postgraduate educations earn higher
wages and remain in the labor market longer.
(5) The private rate of return on investment in postgraduate education is 10% or more. The
social rate of return, including benefits from knowledge spillovers, may be much higher.

Policy implications based on the analysis in this paper are as follows.
(1) Given the trend toward advanced technology and the growing demand for high-level
human capital, postgraduate educations are important to revitalize the Japanese economy.
(2) The expansion of postgraduate education may contribute to narrowing the wage gap
between male and female workers and increasing the labor force participation of elderly
people in the long run.
(3) When analyzing the economic effects of education and comparing wage levels amongfirms or institutions, it is desirable to distinguish between undergraduate and postgraduate
education.

The future of the postgraduate wage premium depends on both the supply of
postgraduates and the demand for high-skilled labor. Because the trend toward advanced
technology is expected to continue, the postgraduate wage premium may increase further if
the increase in the supply of postgraduate degrees does not catch up to the increase indemand for postgraduate workers.

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Table 1 The number of new postgraduates who obtained jobs in 2011
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
Annual GrowthMA39,496
43,13743,30145,217
48,20050,61853,43755,26455,02452,05254,004
3.2%

Ph.D.
7,454
7,697
7,896
8,531
8,723
9,149
9,872
10,23910,537
9,772
10,150
3.1%(Source) The School Basic Survey (Ministry of Education, Culture, Sports, Science andTechnology (MEXT)).

Table 2 The number of new postgraduates by industry
MA
Total
Agriculture & Forestry
Fishery
MiningConstruction
Manufacturing
Electricity, Gas & Water Supply
Information & Communication
Transportation
Wholesale & Retail
Finance & Insurance
Real Estate
Professional & Techinical Services
Accomodations & Restaurants
Personal Services & Amusement Services
Education
Health Care & Welfare
Compound Services
Services N.E.C.
Government
Industries Unable to Classify(Source) The School Basic Survey in 2011 (MEXT).

- 16 -

54,186
181
16
100
2,257
22,710
1,144
5,408
1,026
1,687
987
250
3,317
161
272
5,026
3,680
261
1,563
3,125
1,015

Ph.D.
10,160
21
3
3
87
1,392
30
246
18
65
44
15
1,211
3
4
3,657
2,674
16
141
319
211

Table 3 The share of workers with postgraduate qualifications by age group
Age
Groups
20-24
25-29
30-34
35-39
40-44
45-49
50-54
55-59
60-64
65-69
70-74
75-79
80-84
85Total(1) Engaged inWork(thousands)
4003.96196
7221
7379.16711.46442
6495
7735.74761.62934.31675.9
861.8
364.2
129
63374.5(2) University
Graduates
890.4
2051.5
1995.4
1815.6
1681.6
1704.21563.11373.3
713
323.7
165.5
79.9
31.6
9.5
14398.5(3) Graduate
SchoolGraduates
21.8
236.2
248.3
211.3
151.9
130
96.8
84.1
51.2
23.8
10.7
5.5
1.2
0.3
1273.1(4) (3)/(1)(5) (3)/[(2)+(3)]

0.5%
3.8%
3.4%
2.9%
2.3%
2.0%
1.5%
1.1%
1.1%
0.8%
0.6%
0.6%
0.3%
0.2%
2.0%

2.4%
10.3%
11.1%
10.4%
8.3%
7.1%
5.8%
5.8%
6.7%
6.8%
6.1%
6.4%
3.7%
3.1%
8.1%

(Source) The Employment Status Survey in 2007 (Ministry of Internal Affairs andCommunications).

Table 4 Sample distribution by education
Log Income
FemaleJunior highschool
Senior highschool
Vocational school
Junior college
University
Graduate school
25-29
30-34
35-39
40-44
45-49
50-54
55-59
60-64
65-69
70-74
75-79
80-84
Self-employedNon-regular employee(1) All Workers
14.792
0.408
0.109
0.425
0.121
0.088
0.235
0.021
0.101
0.117
0.119
0.108
0.104
0.104
0.123
0.074
0.044
0.024
0.012
0.005
0.105
0.343

(2) Undergraduates
15.2370.253(3) Postgraduates
15.534
0.152

0.143
0.139
0.126
0.117
0.118
0.109
0.095
0.049
0.023
0.011
0.005
0.002
0.065
0.230

0.186
0.195
0.166
0.119
0.102
0.076
0.066
0.040
0.018
0.008
0.004
0.001
0.048
0.149

(Note) The figures are calculated from the Employment Status Survey in 2007.

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Table 5 Postgraduate wage premium relative to workers with only undergraduate education

All workers
Regular employees
Self-employed

Male
21.9%
18.9%
53.8%

Female
36.6%
36.4%
31.1%

All
29.4%
24.3%
55.7%

(Note) The figures are calculated from the Employment Status Survey in 2007.

Table 6 Estimation results of the wage functions

FemaleJunior hischool
Senior highschool
Vocational school
Junior college
Graduate school
Graduate*Female
25-29
30-34
35-39
40-44
45-49
50-54
55-59
60-64
65-69
70-74
75-79
80-84
Self-employedNon-regular
Adj R-squared(1) Male & Female （2) Male & Female
Coef.
Coef.
***
***
-0.5971-0.5952(-3414.60)(-3404.86)******-0.5270-0.5272(-1741.57)(-1741.30)******-0.3543-0.3541(-1734.42)(-1733.17)******-0.2499-0.2504(-897.35)(-895.53)******-0.2017-0.2007(-629.96)(-626.71)******
0.15950.1816(324.15)(263.34)***
0.1445(96.21)******0.10450.1048(267.98)(267.24)******0.21220.2126(559.12)(558.03)******0.30450.3046(803.47)(803.22)******0.38280.3829(992.06)(991.81)******0.42970.4298(1103.17)(1102.85)******
0.45830.4583(1174.39)(1174.5)******
0.46440.4645(1218.88)(1218.81)******
0.29010.2902(675.36)(675.16)******0.08760.0877(176.34)(176.20)******0.04550.0455(74.56)(74.46)******0.01790.0178(22.35)(22.39)******0.00940.0094(8.12)(8.11)******-0.7002-0.7005(-2457.09)(-2458.17)******-0.6411-0.6412(-3469.41)(-3468.65)
0.47680.4769(3) MaleCoef.

（4) Female
Coef.

-0.5130(-1452.64)-0.3052(-1286.42)-0.2789(-766.46)-0.1564(-266.50)
0.2151(361.50)***

0.1932(363.16)0.4144(809.90)0.5808(1137.79)
0.7174(1373.94)
0.7788(1473.47)
0.8042(1525.66)
0.7805(1529.74)
0.4639(827.32)
0.1951(308.25)0.1207(160.48)0.0999(104.07)
0.0466(33.72)-0.5706(-1721.46)-0.3952(-1508.10)
0.3660

***

***
***
***
***

***
***
***
***
***
***
***
***
***
***
***
***
***

-0.4955(-923.86)-0.3645(-987.62)-0.2135(-497.75)-0.2166(-515.48)
0.2319(170.84)***

0.1001(185.16)0.1140(212.40)0.1016(189.45)
0.1062(195.91)
0.1330(244.32)
0.1458(265.97)
0.1526(280.91)
0.0931(146.05)-0.0150(-19.53)0.0492(49.34)0.0274(20.29)0.1249(64.27)-0.9380(-1822.65)-0.8226(-3252.37)
0.3981

***

***
***
***
***

***
***
***
***
***
***
***
***
***
***
***
***
***

(Notes) WLS estimates with t-values in parentheses. *** Significant at the 1% level. Male,
university graduate, age 20-24, and regular employee are used as reference groups.

- 18 -

Table 7 Postgraduate wage premium by type of employment
All workers
Regular employees
Self-employment(1) Male & female
***
0.182
(324.15)***0.207(434.23)***0.445(126.86)(2) Male***
0.215(361.50)***0.224(478.34)***0.479(123.90)(3) Female
***
0.232
(170.84)***0.249(167.76)***0.232(28.91)(Notes) WLS estimates with t-values in parentheses. *** Significant at the 1% level.

Table 8 Discounted present value of lifetime income and the rate of return on investment inpostgraduate education (thousand yen, %)(1) Undergraduates(2) Postgraduates(3) Difference [(2)-(1)](4) Rate of return (a)(5) Rate of return (b)Male
122,979
158,408
35,43011.8%
16.0%

Female54,951
82,577
27,6269.6%
13.1%(Notes) The figures are estimated from the Employment Status Survey in 2007. Labor
participation rates by sex and age classes are adjusted. Discount rate is assumed to be
3% per annum. The rate of return (a) and (b) assume annual school and living
expenses to be 3 million yen and 1.5 million yen, respectively.

- 19 -

Figure 1 Age-wage profiles of regular employees(Note) Estimation is made by cell data from the Employment Status Survey in 2007.

Figure 2 Age-wage profile of male self-employed workers(Note) Estimation is made by cell data from the Employment Status Survey in 2007.

- 20 -

Figure 3 Labor participation rates by sex and education(Note) Labor participation rates by age groups are calculated from the Employment Status
Survey in 2007.

- 21 -