ISS Discussion Paper Series F-154

Does downsizing take a toll on retained staff?
An analysis of increased working hours during recessions
using Japanese micro data
March 2011
F-154

Yuji Genda*, Sachiko Kuroda**, and Souichi Ohta***
Institute of Social Science
The University of Tokyo

Abstract

Using official household micro data from the Labour Force Survey, thispaper examines the increase in the working hours of regular male
employees in Japan under recession from the late 1990s to the early 2000s.
The most important findings of this paper are that working hours tended to
be longer among male regular employees of firms in which (1) there wasmajor employment adjustment, (2) substantial increase in proportion of
non-regular workers, and (3) wide variance in regular wages. The results
suggest that the existence of a large amount of fixed duties that arenecessary to maintain internal organization and transition from thetraditional employment system are the main factors that explain theincrease in the working hours during the recession in Japan.

***

The University of Tokyo (e-mail: genda@iss.u-tokyo.ac.jp)
The University of Tokyo (e-mail: kuroda@iss.u-tokyo.ac.jp; from April 2011 onward,
s-kuroda@waseda.jp)*** Keio University (e-mail: ohta@econ.keio.ac.jp)

This empirical analysis was conducted as a part of the project at the Statistical Research and Training
Institute, Ministry of International Affairs and Communications, Japan. A part of the data used in thisarticle are taken from the Japanese Labor Force Survey housed at on-site data center of the Statistical
Research and Training Institute. Information on access to the data can be obtained by contacting Yuji
Genda, Institute of Social Science, the University of Tokyo, 7-3-1 Hongo Bunkyo-ku, Tokyo 113-0033,
Japan. E-mail: genda@iss.u-tokyo.ac.jp. The rest of the data and all codes to replicate the tables in thisarticle can be obtained from Sachiko Kuroda, Faculty of Education and Integrated Arts and Sciences,
Waseda University, 1-6-1 Nishiwaseda Shinjuku-ku, Tokyo 169-8050, Japan. E-mail:s-kuroda@waseda.jp. This research is supported by Program for Promoting Social Science Research
Aimed at Solutions of Near-Future Problems “Creation of Employment System that enables Lifelong
Growth for All People” (commissioned by the Ministry of Education, Culture, Sports, Science andTechnology) and Program of Intergenerational Equity (the grants from the Ministry of Education, Culture,
Sports, Science and Technology).The remaining errors are solely of our own.

Employees’ working hours usually fluctuate with amounts of business, and employees
generally work longer hours in periods of boom than in recession. However, in Japan,
the exact opposite phenomenon has been observed: the average working hours of maleregular employees largely increased from the late 1990s to early 2000s, when Japan’s
economy underwent a recession. According to the OECD iLibrary, there has been asteady decline in Japan’s average annual working hours over the past several decades.
However, since the data sample of the OECD includes part-time workers, the unusual
fact that the working hours of Japanese full-time regular employees have increased
under prolonged recession from the late 1990s to the early 2000s has not been noticed.
To the best of our knowledge, this is the first analysis of the counter-cyclicalphenomenon of an increase in working hours even under severe recession.
Long-term employment and seniority-based wage payments are well-known,
unique characteristics of Japanese firms. One of the theoretical explanations of thesecharacteristics is that it enables the accumulation of firm-specific human capital(Hashimoto and Raisian 1985, Mincer and Higuchi 1988). The other explanation is that
rapid technological innovation and shortage of skilled workers led to the developmentof internal labor markets during the rapid growth era of the 1960s (Koike 1988). Boththese theories predict that labor-hoarding behaviors during recessions may be prevalent
among Japanese firms.
Due to the substantial cost of training as well as high hiring and firing costs, it isbelieved that Japanese firms avoid a reduction in the number of employees and attempt
to cut personnel costs by reducing the working hours of incumbent employees when
there is a recession in the economy. Such a labor hoarding practice is rational under theassumption that the negative unanticipated shock is believed to be temporary or minor.
On the other hand, when the negative shock is expected to be persistent and substantial,
even firms with a propensity to hoard labor are compelled to reduce the number of
employees by freezing hiring and accelerating dismissals. Under such a situation, if
there are certain fixed activities in a firm that are conducted almost independently of the
production level, the workload on every remaining employee may increase in spite ofrecession. Consequently, the small number of employees who are retained by thedownsizing company may need to work longer hours.
Furthermore, since the end of the 1990s, an increasing number of Japanese firms
have introduced measures to reduce employment through policies such as payment of
extra retirement allowances. In addition, certain studies emphasize that the Japaneseemployment system has been in transition since the end of the 1990s (for example,
Genda 1998, Ono 2010, Morishima 2010). They suggest that employment has become1more flexible in Japanese firms as aspects of seniority such as age and tenure no longer
play dominant roles in determining wages, and these firms are more likely to pay wages
based on the short-term performances of individual workers. The increasing possibilities
of dismissal along with transition of the wage payment system during this period may
have induced workers to work longer hours. In addition, since the late 1990s, a large
number of non-regular workers are being employed as a more effective method tosecure the flexibility of wage and employment. According to the Labour Force Survey,
in 2010, 34.3 percent of the total Japanese employees were non-regular staff such as
part-time, dispatched, and contract workers. Thus, the increase in the number ofuntrained non-regular employees may increase the job burden of regular permanent
workers who manage these non-regular workers in terms of managing teams andadjusting team production.
Overview
Japan’s employment system is characterized by long-term employment that begins
immediately after the completion of education and lasts until the age of mandatory
retirement is attained. 1 An obvious consequence of this so-called “lifetime”
employment system is a long job tenure and high job-retention rates for prime-aged
male workers. A “seishain,” or a regular employee, works full-time and is on an
employment contract that does not specify the date of termination; such an employee isusually believed to be on the lifetime employment track.2 In this section, we describe
the manner in which the number of working hours for male regular employees haschanged during the prolonged recession since the early 1990s (the so-called “Japan’s
lost decade”).
Figure 1 presents the series of average weekly number of working hours ofprime-age (25–49) male regular employees and the male unemployment rate from 1986
to 2007. Both series have been adapted from The Special Survey of the Labour Force
Survey (Roudouryoku Chousa Tokubetsu Chousa, 1986–2001) and the data obtained
1

Contrary to public belief, Kato (2001) emphasizes the enduring nature of the lifetime
employment practice in Japan, using data until 1997. Further, Kambayashi and Kato (2011) alsofind that job stability of regular employees did not fall much in particular during the first five
years of Japan’s lost decade. However, they also suggest that the job stability of regular
employees eventually fell slightly from the end of the 1990s to early 2000. Further data
accumulation is necessary to test whether the traditional Japanese employment system has
undergone a complete transformation in response to prolonged recessions.
2
In certain occasions, even if an employee satisfies the two conditions, he/she is not considered
as a “regular” employee. Thus, numerous surveys, including the Labour Force Survey, directly
ask what the respondent is called by the employer in order to clearly classify regular andnon-regular workers.
2

from the special questionnaire of the Labour Force Survey (Roudouryoku Chousa
Tokutei Chosahyo, 2002–2007).3 Both surveys are conducted by the Statistics Bureau,
Ministry of Internal Affairs and Communications, Japan.
It is evident from Figure 1 that the number of working hours of prime-age maleregular employees declined rapidly from the end of the 1980s to early 1990s. This
reflects a reduction of the (straight-hour) workweek from 48 hours to 40 hours as
mandated by the 1988 amendment to the Labor Standards Act and the effect of theeconomic recession that occurred in the early 1990s. After the sharp decline in the early
1990s, the number of working hours remained around 48 hours per week until 1997.
However, after 1998 when the recession worsened, the number of working hours surged
close to the number of working hours during the economic boom in the end of the 1980s.
In other words, the number of working hours per week surged from 47.7 hours in 1998
to 50.2 hours in 2004, which is close to the level recorded in 1988 (51.1 hours).4
Together with the domestic recession that began in the early 1990s, 1998 was the year
when the Asian financial crisis hit the entire area of Asia, including Japan, which further
dampened the economy. This was the time when Yamaichi Securities, one of the leading
financial firms at the time went bankrupt and the Bank of Japan introduced azero-interest rate policy to prevent the economy from falling into further recession.
However, the recession had deepened after 1998 until the early 2000s and theunemployment rate rose rapidly to an unprecedented level during the period, as shownin Figure 1.
Further, Figure 2 presents the divergence in the working hours among certain
male regular employee groups for two specific years in which the working hours
peaked—1988 and 2004. Although the average number of working hours is relatively
the same for both 1988 and 2004, several other different features are evident from
Figure 2. First, in 1988, employees in their 20s were the group with the longest working
hours among all the age groups: the younger an employee is, the longer he/she works.
However, in 2004, the group with the longest working hours was employees in their 30s.
Moreover, employees in their 40s who used to work relatively lesser number of hours in
the 1980s began working longer hours to equal those in their 20s. Second, in 1988,
3

Unless noted otherwise, all analyses from this point forward are based on calculations using
weights provided by the Statistics Bureau, Ministry of Internal Affairs and Communications,Japan.
4
Although not shown in the figure, even after controlling for demographic and compositionalchanges that occurred during the two decades, such as a rising proportion of elderly persons,lower fertility rates, increasing number of years in education, and decline in marriage rate, theseries presented in the figure remains almost the same. Using a rich time-use survey, Kuroda(2010) reports similar trends for full-time Japanese workers.
3

highly educated employees worked lesser number of hours than less-educated ones.
However, in 2004, there was an increase in the number of working hours of highly
educated employees. Lastly, white-collar employees worked for greater number of hours
than blue-collar employees did in 1988; this tendency increased further in 2004.
Two aspects may be emphasized from the casual observations above. First, it
appears that the number of working hours changed counter-cyclically from the end of
the 1990s to early 2000s. This may be regarded as a rather unique phenomenon, inparticular since the typical practice adopted in Japanese firms during previous
recessions was to reduce the number of working hours as much as possible in order toprotect employees from dismissal5; therefore, the number of working hours changed
pro-cyclically in the past. Second, during this period there was a change in thecharacteristics of male employees who worked relatively longer hours. The employees
whose number of working hours increased during this period were in their 30s, highly
educated, and white-collar workers. What has led to these changes during this period?
In order to investigate the reasons for this increase in the number of working hours, inthe next section we introduce four possible effects that may explain the reasons for thecounter-cyclicality in number of working hours.
Underlying Mechanisms
In this section, several hypothetical effects are presented in order to explain why
working hours of prime-age male regular employees tended to be longer during therecession. As already indicated, until Japan underwent the long recession in the 1990s,
the employment adjustment in Japanese firms was characterized by “labor hoarding” inwhich, during recession, there was a gradual adjustment in the number of employees;
however, there was a sharp decrease in the number of working hours. The following two
factors are considered to have contributed to this phenomenon.
One is the fact that since training employees is a rather time-consuming process,firms are required to recruit a certain proportion of employees required in the futuremuch ahead of time. This implies that firms are unable to adjust their labor input freely
5

There is a strand of literature that studies the speed of employment and adjustment of working
hours adjustment for Japan and other countries using both aggregate and industry-level data (forexample, Shinozuka and Ishihara 1976, Tachibanaki 1987, Hashimoto and Raisian 1988,
Abraham and Houseman 1989). A large number of these literatures suggest that the adjustmentof employment is significantly slower in Japan than in other countries. Further, Hildreth andOhtake (1998) conducted a detailed examination using plant-level data and found that Japanesefirms respond to negative shocks in a slightly different manner than US firms, for example bytransferring employees within firms.
4when faced with fluctuations in product demand. Since Japanese firms tend to invest
actively in firm-specific human capital, the speed of employment adjustment in terms ofthe number of employees is likely to become slow. Instead, they control the number ofworking hours of the employees in order to cope with changes in optimal labor input.
The other factor is that large costs are incurred in labor adjustment. In order toinvest intensively in firm-specific human capital, Japanese firms had to assure
long-term employment to their employees in an implicit manner. In order to support
such an employment policy of Japanese firms, several Japanese labor case laws also
place high priority on maintaining employment levels in firms.
Hence, we first present a rather simple model that considers the abovementioned
factors. Thereafter, we will consider the manner in which changes in the Japanese
economy during the 1990s have brought about the changes in the premises for thismodel.
Basic ModelIn this model, we assume that a firm exists forever but its employees exist only for two
periods. The first period is the “training period” and the second one is the “production
period.” For the sake of simplicity, the first period is purely for training and thecontribution of employees to production is present only in the second period. The input
factors of the second period, that is the production period, include “number of
employees” and “working hours.” The production function depends only on labor;
therefore, the production level at time t can be expressed by y

F h ,N, where ht

denotes the working hours used for production during the second period and Nt-1
denotes the number of workers hired in the previous period (F1 > 0, F2 > 0). In otherwords, the number of workers in period t is determined in period t - 1 on the basis of the
expectation of the production level in period t and thereafter.
This implies that the layoff cost is infinite and that the firm cannot adjust the
number of workers at all after they have been hired by the firm. On the other hand, let
us assume that the number of working hours necessary for production in period t can beascertained after the realization of the demand level in period t, given that the number ofworkers has already been determined in the previous period.
Further, we assume the following situation regarding the wages. The wages are tobe paid at the end of the second period. The wage level depends only on the number ofworking hours in the second period and is independent of the training hours in the first
period. Therefore, the longer the production hours in the second period, the higher the5total wage. Following Hamermesh (1993), the wage level paid in the second period isexpressed by w(ht); in other words, the wage level is a function of the number ofworking hours. No wage is paid during the first period because there is no contribution
to production. However, this assumption for simplification also reflects theseniority-based wage system prevalent in large Japanese firms.6
Firms face uncertainty regarding the product price p in the future. Firms are awareof the current price but only know the distribution of the future price. Based on all theseassumptions, firms attempt to maximize the expected profit function given below interms of the number of working hours and workers.
（1）

∞

Π

E

1

r

p F h ,Nw h N

Ωwhere r is the interest rate7, E is the expectations operator, and Ω is the information set
available to firms in period t.
The first-order necessary conditions for profit maximization are
Ep

F h

,N

w h

|Ω

0

(2)

w′ h

N

0,

(3)

and
p

F h

,N

where (3) indicates that the number of working hours in period t + 1 are a function of
the price level in period t + 1 and the number of employees determined in period t.
Substituting (3) into (2) determines the number of employees hired in period t. The
labor-hoarding behavior of the firm is evident from the above two equations. The
number of employees hired in period t is determined completely independently of theprice level at that time, and the number of working hours necessary for production inperiod t is determined only by the number of workers hired in the previous period and6

A trend in Japan is that wages rise until workers attain around the age of 50. This phenomenon
is termed the seniority-based wage system. Although wage-setting policies differ from firm tofirm, the actual wage curve reveals that salaries rise as seniority increases. This reflects that innumerous firms, greater priority is given to age and tenure than to other criteria since humancapital (or skills) is believed to accumulate with age and tenure. For a more rigorous discussion
on the human capital theory, see Becker (1964).
7
The interest rate is assumed to be constant over the entire period.
6the price level of the current period t. This implies that if the price level in period t were
to become temporarily low, firms would decrease the number of working hours but
retain the number of employees.
However, during the recession of the 1990s there was a reduction in the number of
employees in Japanese firms and an increase in the number of working hours of these
employees. How can this phenomenon be explained? Several possible hypotheses arepresented below.
The fixed-duty effect
The model developed above indicates that the shifts in the price distribution in period t+ 1 affect the number of workers in period t. For example, when firms expect a decreasein future prices (the price distribution shifts to the left), the current number of workers
will be reduced. In other words, if a negative shock is expected in the long-term forecast,employment will be reduced. In addition, if there are certain activities in a firm that are
conducted independently of the production level, the number of working hours of eachretained employee will increase as a result of the large-scale reduction in the number of
employees.
Now it is assumed that employees who underwent training in the first period are
not only engaged in ordinary production activities but also in activities that are notprone to change on the basis of changes in demand for their products or services. The
existence of such fixed duties may be easily understood if the actual operations of a firm
are considered. For example, “internal control” jobs such as accounting, planning andhuman resources, and activities in the factory to prepare for production such as
overhauling and repair of machinery are necessary for the business operation of a firm
and are independent of the demand level. Therefore, in the following discussion, we
assume the existence of such “fixed” duties that are independent of the production level,
and that these duties always require D number of hours to be invested by all employees
in the second period as a whole. Assuming that h is the average working hours per
worker for such duties in period t, the relation h N
D holds. If we assume thatthe average total number of working hours of workers in the second period are
represented by ht , where ht ht
modified in the following manner.

Π

E

1

r

hdt holds, then the profit function of (1) can be

p F h ,N

w h

7

D
N

N

Ω

(4)

Further, we suppose, for the sake of simplicity, that hourly wage rate is constant; inother words, w hwh ,. Then, the total labor cost can be denoted in the following
manner: w h N

w h

N

wh N

wD. If there is a fall in the expected

price in period t, the number of workers hired in the period t - 1 will decrease and thenumber of working hours utilized for production, which are determined in period t, will
also decrease. On the other hand, the number of working hours for the fixed duties per
worker will increase according to the overall reduction in the number of workers. It
must be noted that if the reduction in both price and the number of workers due torecession is significantly large, then the increase in number of working hours for fixed
duties may overtake the decrease in the number of working hours caused due toreduction in production. As a result, it is possible that there is an overall increase in thenumber of working hours.
This situation can occur during recession in firms that require the fulfillment of alarge amount of fixed duties for managing internal labor markets. Specifically, we canfind that the total number of working hours per employee h D⁄N
increase with adecline in the number of employees N
if dlnht/dlnNt-1<D/htNt-1. In other words, thesmaller number of total employees need to work for longer hours when working hours
required to fulfill fixed duties D are sufficiently large as compared with the total
production hours (h N ) and its ratio is larger than the relative elasticity of production
hours to employment.
The worker-replacement effectAn important feature of Japan’s lifetime employment system is the two-tier structure
within a firm. In other words, in order to protect regular employees from recessions,numerous Japanese firms hire non-regular employees (fixed-term contracts or part-timeworkers) on a regular basis as a buffer for contingency. Therefore, a typical practice innumerous Japanese firms was to reduce the number of non-regular workers during arecession by ceasing contract renewal while hoarding regular workers as much as
possible. This practice is closely related with the strict employment protection
legislation for regular employees in Japan, which has been established by theaccumulation of case laws over the past several decades. In such an environment, firms
invest considerable resources for regular employees to accumulate job-related skills,
while investment on non-regular employees remains relatively small.
During the 1990s, under a considerably uncertain economic environment,
numerous firms changed the proportion of regular and non-regular workers by8increasing the ratio of non-regular workers in order to prepare for the impending
downturn. According to the Labour Force Survey, the proportion of non-regular workers
was 16.4 percent in 1985, but grew rapidly to 20.9 percent in 1995, and 32.6 percent in2005. In other words, the ratio of non-regular workers almost doubled during theprolonged recession and non-regular employees replaced regular employees innumerous jobs.8
Our next explanation for the increased working hours of male regular
employees comes from this rapid increase in the number of non-regular workers during
the prolonged recession. If regular and non-regular employees are not perfect substitutes,
which is a reasonable assumption since the investment on regular employees is muchlarger than that on non-regular employees, the increase in the number of non-skilledworkers at the workplace may have shifted the burden of fulfilling fixed duties andsupervision to the retained regular employees. If this is the case, the greater the ratio of
non-regular employees at the workplace, the greater the burden that shifts on to regular
employees; this increases their number of working hours.
This concept can be introduced into our model as follows. The assumption here isthat firms, as before, cannot adjust the number of regular employees after an economic
shock, but they can adjust the number of non-regular employees. Then, let us assume
that the production level is a function of three factors: the working hours of regular
employees, number of regular employees, and number of non-regular employees. In
other words, if the number of non-regular employees is denoted by M, then y. For the sake of simplicity, it is assumed that the number of working hours
F h ,M ,Nof non-regular workers and wage level are fixed.
Further, we assume that regular workers have to supervise non-regular workers,
and the total hours necessary for the fulfillment of fixed duties are given byD

D M , D′ M

0.

(5)

Then, this value divided by the number of regular workers, as discussed in the previous
section, yields the number of hours spent in the management of non-regular workers per
regular worker. By applying these modifications to (4), we can formulate the profit
8

Note that even though we used the term “replacement,” it does not necessarily imply firing
incumbent regular employees and replacing them with non-regular employees. Rather, thereplacement of regular workers with non-regular workers occurred among new hires, i.e., hiring
non-regular employees instead of regular-employees. Genda, Kondo, and Ohta (2010) foundthat the unique school-based hiring system in Japan leaves the youths in non-regular
employment for a longer period than in the United States if they fail to obtain regular jobs soonafter graduation.
9

optimization problem.
On the basis of this modified model, it may be indicated that when Japanesefirms face an unstable economic environment, they attempt to restrain the employmentof regular workers and increase the number of non-regular workers. However, this, inreturn, may increase the total working hours spent in team management, coupled withthe likely reduction in the number of regular workers, prolong the working hours of
regular workers.
The dismissal-threat effectAlthough retaining regular workers was the typical practice adopted by Japanese firms,
the Japanese labor market underwent an unprecedented huge employment adjustmentpressure due to the large and persistent negative economic shocks that occurred in thelate 1990s. Under such an environment, certain firms were compelled to reduce thenumber of employees. The dismissal-threat effect describes the phenomenon that thegreater possibility of dismissal in such an economic scenario induced workers to work
longer in order to avoid being laid off. This may be particularly true for white-collar
workers, who work long and hard in an attempt to prove to one’s employer that he/she israther hardworking and thus must not be the one to be laid off.
Suppose, for example, that there exits asymmetric information about
productivity or performance level between employers and employees: workers know the
precise level of their productivity; however, employers only know the value that
contains the measurement error. This can happen particularly when the workers are
involved in team production or projects that require a long time for the firm to evaluate
workers’ actual contribution to them. Further, suppose that both parties know that long
working hours can raise the workers’ observed performance level. If the firm uses suchobserved performance level as an important criterion for layoff, workers are induced towork longer hours simply to influence the firm’s evaluation of productivity.9
The wage-incentive effect
Our final hypothesis is centered on the concept that larger earnings inequality would
induce workers to work longer since extra number of working hours would imply
greater wages if there is a larger inequality in earnings among workers. The original
9

This explanation is rather close in spirit to the one discussed in Landers, Rebitzer and Taylor(1996), which argues that large law firms use number of hours worked as an indicator of
associates’ propensity to work hard. Their paper indicates that reliance upon number of working
hours as an indicator of performance leads to a rat-race equilibrium in which associates work
long hours.
10

concept has been given by Bell and Freeman (2001), who find that the large differencesin the number of working hours between the United States and Germany can be
explained by the earnings inequality. They indicate that since inequality is much larger
in the United States, the workers in US are more likely to work longer hours to seek
higher wages.
During the late 1990s, inequality in earnings expanded particularly among highly
educated male employees.10 This may have been induced by the introduction of theperformance-based pay system, which was widely spread out in Japan during this period.
Since the performance-based pay system is a wage system whereby the wage is paid on
the basis of the short-term explicit performance of the worker, the marginal benefit frommaking greater effort is likely to increase if such a system is introduced. Therefore,
employees tend to work longer hours in order to achieve better production performance.
Data and Methodology
Data
The primary sources of data for this study are the Special Survey of the Labour Force
Survey and the data obtained from the special questionnaire of the Labour Force Survey.
The Special Survey of the Labour Force Survey was conducted annually in
February from the early 1980s until 2001, and each year’s sample comprised
approximately 90,000 individuals over the age of 15 in approximately 40,000 randomly
selected households. In 2002, the annual Special Survey was replaced with the monthly
Labour Force Survey that incorporated a special questionnaire with a sample size of
23,000 individuals each month. For this study, in order to avoid the seasonality bias,
only the February samples must be used; however, due to lack of an adequate sample
size, we combined the surveys taken from January to March. Both surveys arecross-sectional and include the same questions pertaining to annual earnings, detailed
employment status, employer characteristics, and basic demographic characteristics,
thereby making both surveys inter-related. We limit our samples to prime-age maleregular employees aged from 25 to 49 years who work for private firms. Table 1
presents the summary statistics.

10

Kambayashi, Kawaguchi, and Yokoyama (2008) report that the wage variance among
Japanese males expanded after 1997, and find that this expansion can mostly be explained by anincrease in variance within groups. Moreover, Rebick (2005) also finds that dispersion inearnings among middle-aged university-educated men has increased particularly in large firms,
and argues that there may be certain effects of new compensation schemes.
11Methodology
We estimate the following nested reduced form model that incorporates possible
explanations that reflect the fours effects mentioned in the previous section for theincrease in number of working hours during the severe recession.
lnh ,∑ X , α,∑ Y ,β ,∑ m, γ,

u,

,

(6)

where lnhi is log weekly number of working hours of individual i, Xij represents thepossible factors j (j = 1,2,3,4) that describe the four effects described in the previous
section, Yik represents the observed individual characteristics, ml represents other control
variables, ui is an error term, and subscript t represents time. Each variable is explainedin the following manner.
Possible factors
First, for the fixed-duty effect, we included the rate of change in the total number ofworkers (including regular and non-regular employees, males and females) using datafrom the Labour Force Survey. The total number of workers were first grouped byindustry (“construction,” “manufacturing,” “transport and postal activities,” “wholesale
and retail trade,” “finance, insurance, and real estate,” and “other service industries”)
multiplied by firm size (500 and over, 30–499, and less than 30 employees). Thereafter,
we calculated the rate of change by subtracting the current number of employees fromthe number of employees in the same group five years earlier. The rate of change in thenumber of employees reflects the magnitude of labor adjustment that occurred during
the period under study.
Second, for the worker-replacement effect, we calculated the number of
non-regular workers grouped by industry (“construction,” “manufacturing,” “transportand postal activities,” “wholesale and retail trade,” “finance, insurance, and real estate,”and “other service industries”) multiplied by firm size (500 and over, 30–499, and lessthan 30 employees) and divided it by the total number of employees in the same group.
This non-regular worker ratio is incorporated as a proxy for the magnitude of worker
replacement. In order to capture the effect of rapid increase in the worker replacement
ratio, we also subtracted the non-regular worker ratio from the ratio calculated five
years ago for the same group and included the rate of change in the estimation.
Third, for the dismissal-threat effect, we calculated the possibility of dismissal
in the following manner. First, we grouped the number of male regular employees Nz (zdenotes group) by firm size (500 and over, 30–499, and less than 30 employees)
12multiplied by cohort (grouped by five years) and education (high school diploma or less,junior or technical college (2 years) diplomas, university diploma or more). Then, we
subtracted Nz from the number of male employees present five years ago for the samegroup z in order to calculate the dismissal rate for each group (Nz,t-5- Nz,t)/ Nz,t-5*100.
The higher the dismissal rate, the higher the possibility of the corresponding group to bedismissed from employment.11
Finally, for the wage-incentive effect, we cannot directly use information that
identifies whether each individual is hired in a firm using the performance-based pay
system. Instead, we examine the effect by incorporating a divergence of wages to theestimation equation, following Bell and Freeman (2001). Specifically, we use data fromthe Basic Survey on Wage Structure (Chingin Kouzou Kihon Toukei Chousa) conductedby the Ministry of Health, Labour, and Welfare of Japan, which is the most trusted
official survey on wages in Japan. These data are collected annually on establishmentsthat have 10 or more regular employees; the sample size of the survey is almost 80,000
establishments. From this survey, we employ the “Decile dispersion coefficient (＝[9thDecile - 1st Decile]/2 × Median)” as a proxy for the wage dispersion, grouped by firm
sizes (1,000 and over, 100–999, and 10–99 employees)12 multiplied by age group(25–29, 30–34, 35–39, 40–44, 45–49) and education (high school diploma or less,junior or technical college (2 years) diplomas, university diploma or more).
Individual characteristics and control variables
With regard to individual characteristics, we included age, age-squared, education
dummies, firm-size dummies, industry dummies, occupation dummies, marital status
dummy (married = 1), child dummy (having a child under six = 1), working spousedummy (working spouse = 1), residential prefecture dummies, and cohort dummies.
Further, with regard to control variables, we incorporate the regional male
unemployment rate grouped by 10 regional blocks (Hokkaido, Tohoku, Southern Kanto,
Northern-Kanoto and Koshin, Hokuriku, Toukai, Kinki, Chugoku, Shikoku, andKyusyu) in order to control for the differences in demand by region. In addition, we
include monthly scheduled cash earnings (amount of contractual cash earnings, notincluding overtime allowance) from the Basic Survey on Wage Structure categorized by
11

Since the change in the number of regular workers also includes factors such as inflows toand outflows of non-regular workers, self-employed, and out-of-labor force, this variable is notnecessarily the best proxy of dismissal rate.
12
Since the Basic Survey on Wage Structure does not include wage information on firms withless than 10 employees, we use information of firms with 10–99 employees to those who workin firms that hire less than 10 employees for the approximation.
13

industry (“construction,” “manufacturing,” “transport and postal activities,” “wholesale
and retail trade,” “finance, insurance, and real estate,” and “other service industries”)
multiplied by firm sizes (1,000 and over, 100–999, and 10–99 employees), age group(25–29, 30–34, 35–39, 40–44, and 45–49), and education (high school diploma or less,junior or technical college (2 years) diplomas, university diploma or more). Further, themonthly scheduled cash earnings were converted into log in real term using informationfrom the Consumer Price Index by prefecture level.13 This is done in order to control
the change in wages since the end of 1990s.
Finally, we added a variable to control for the difference in the age structure
among regular employees. This was done by calculating the ratio of the number ofregular employees in a certain age group to that of employees who are five years
younger: Nz-1,t / Nz,t, where Nz,t is the number of regular employees in age group z inperiod t. If the ratio is equal to one, it implies that the number of regular employees who
are five years younger is same as the number of employees in the selected age group. If
the ratio is over 1, it implies that the number of younger employees are greater; if theration is lower than 1, it implies that the number of younger employees are less than theselected age group.
Using the above variables, we estimate equation (6) for the following three
periods: (a) 1998–1999, (b) 2002–2004, and (c) 2006–2007. 14 The years 1998 and1999 are the first two years when the Japanese economy underwent further recession.
The period 2002–2004 is when the average number of working hours andunemployment rate both recorded their peak since 1998. The years 2006 and 2007 arethose of mild economic recovery before the global financial crisis hit the economy again
in 2008.
We first estimate the weighted least squares for each period using samplingweights provided by the statistical bureau. In Japan, there is a government policy
measure to provide subsidies to a firm that undergoes a severe downturn in business inorder to protect regular workers’ employment. All the employees hired by firms that
13

Monthly cash earning is determined on the basis of the statutory work week; therefore, it isindependent of actual working hours. We use this variable in order to avoid negative correlationthat may occur when hourly wage is calculated as the individual’s annual income divided byannual work hours (= weekly hours worked multiplied by 52 weeks). However, when we used
instrumented hourly wages calculated from this hourly wage, we obtained similar results.
14
While the left-hand side of our estimation is the number of weekly hours worked byindividual employees, the explanatory variables we incorporated as possible factors to test theabove effects are all calculated using aggregated data. There is no simultaneous bias for
estimation as we assume that employees decide their individual working hours, given theaggregate working conditions that they encounter.
14

receive such subsidies must either take one day off per month or shorten work hours
below the legal workweek (40 hours per week). In order to avoid the effect of such a
policy, we limit our samples only to those who work for over 40 hours per week.15 In
addition, we also estimate the Tobit model (censored below 40 hours) using samplingweights.
Estimation Results
Results regarding possible factors
The estimation results are presented in Tables 2 (weighted least squares: WLS) and 3(Tobit model). It is evident that both tables present similar results.
With regard to the fixed-duty effect, the changes in the number of workers has
a significantly negative sign during the period 2002–2004, thereby suggesting that thiseffect was present during this period. This is the period when the number of working
hours recorded its peak, thereby implying that the huge reduction in the number of
employees due to prolonged recession resulted in an increase in the working hours ofretained regular employees.
Further, the results reveal that the worker-replacement effect also holds during
the prolonged recession. Specifically, the ratio of non-regular workers has asignificantly positive trend for the periods 1998–1999 and 2002–2004. Furthermore, therapid increase in the ratio of non-regular workers also caused the number of working
hours to increase during the period 2002–2004.
With regard to the dismissal-threat effect, the probability of dismissal effect issignificantly positive for 1998–1999, although for the periods 2002–2004 and2006–2007 this probability is insignificant. This implies that this effect was only present
at the beginning of the severe recession.
With regard to the wage incentive effect, our estimation results reveal thatwage dispersion is statistically significant in all periods, thereby implying that theperformance-based pay system, which was widespread in Japan during these periods,
may have pressurized employees to work for longer hours.
In Table 4, the samples are limited to workers in their 30s and 40s, while othercontrol variables are the same as those in Tables 2 and 3. The results are almost thesame as those presented in Table 2. Further, in Table 5, the results of the Probit model
estimation in which the variable in the left-hand side takes 1 if an employee works forover 60 hours per week, and 0 otherwise. In other words, Table 5 indicates which of the
15

Note that even when we include samples of those working for 40 hours or less, however, ouroverall estimation results did not change.
15

four effects is most relevant for employees who work for extremely long hours. It isevident from Table 5 that the fixed-duty and worker-replacement effects are the twomain factors that drove employees to work rather long hours during this period.
It is possible that the results obtained in Tables 2 to 5 are due to the highcorrelation among possible factors. As a robustness check for the multicollinearity, we
check whether the same implications that are evident from these tables hold even if one
or more factors are excluded. The Appendix Table presents the estimation results using
the Tobit model. It is evident from the table that overall the statistical significance aswell as the sign and size of the coefficient are almost the same, which endorses theresults presented in Tables 2 to 5.
Now we examine the results related to other control variables by examining
Table 2. With regard to the years of education, it is evident that those who have longer
years of education tend to work longer during the period under consideration, and thistrend seems to be particularly prevalent during 2002–2004. With regard to occupation
dummies, highly skilled white-collar workers such as professionals and managers tend
to work longer than clerical workers (base) or laborers (blue-collar workers). However,workers in sales, protective services, transportation and communication, which do notnecessarily require high skills, also appeared to work longer in these periods.
Moreover, one of the other important findings is that the real monthly
scheduled income has a significant negative impact on working hours in the periods
2002–2004 and 2006–2007. This may suggest the income effect on labor supply during
these periods; in other words, if the real wage income had fallen, employees would haveavoided consuming normal goods like leisure and preferred to work more. It is evident
from Table 1 that the average nominal wage could indeed be calculated to be lower by
2.7 percent in 2002–2004 than that in 1998–1999. However, there was a serious
deflation in the Japanese economy at the same time; thus, the average consumer priceindex fell by 2.9 percent on average between the abovementioned periods. As a result,the average real wages of regular male employees remained stable or rather increasedslightly during these recession periods. This implies that the income effect could not
explain the increase in number of working hours.
With regard to marital and child dummies, both variables indicate positively
significant results during the three periods. In standard labor supply studies, results thatindicate that a worker who is responsible for housework and childcare tends to work
less are rather usual; however, our estimation reveals the opposite results. The reason
for this is not clear. It may be because prime-age Japanese males—who our study
focuses on—spend very little time, on average, on housework and child-related16

(non-market) work. This is an area for further study.
Which factor most influenced the number of working hours?
The above discussion indicates that the counter-cyclicality of number of working hours
observed from the end of the 1990s to early 2000s in Japan can be explained by a
mixture of several factors. For the period from 1998 to 1999, when there was immensepressure on employment adjustment, increasing risk of dismissal induced employees towork longer hours in order to avoid being laid off. However, in the period 2002–2004,
when both the number of working hours and unemployment rate reached their peaks,
the large-scale reduction in the total number of employees at the workplace induced theretained regular employees to work longer hours. Further, the increase in the number of
non-regular employees during this period also appeared to increase the number ofworking hours of regular employees. In addition, the widespread performance-based
pay system also pressurized workers to work longer hours in order to improve theirperformance.
Then, which of the four factors contributed most to the increase in the numberof working hours in the period 2002–2004 during the severe recession? Table 6 presents
the simulation results that indicate the contribution of each factor toward increasing thenumber of working hours using the results obtained in Table 2.16 It is evident from
Table 6 that the large adjustment of the total number of employees (the fixed-duty
effect) and the increase in the number of non-regular employees (the worker
replacement effect) are the two main factors responsible for the increase in the numberof working hours of male regular employees in Japan. 17
Discussion and Conclusion
This paper addressed the confounding issue of why there was an increase in the numberof working hours of Japanese male regular employees in spite of serious recession fromthe late 1990s to the early 2000s. It has long been said that a typical feature of Japanese
16This simulation was conducted in the following manner. Taking the wage incentive effect as
an example, we obtained the following result in Table 2: log(hour) = const + 0.208(var) + otherterms, where var is the wage variance. This implies that one unit of increase in wage variancewould increase working hours by 20.8%, other things being equal. It is evident from thesummary statistics presented in Table 1 that the change in the average wage dispersion from1998–1999 to 2002–2004 was (Δvar = 0.241–0.236). Therefore, we calculate that the average
working hours derived from the constant term in 2002–2004 was pushed upward by 20.8% ×Δvar, which is 0.035 hours.
17
When we calculate the contribution of the slight increase in real wages on the number ofworking hours during the period 2002–2004, we obtained a rather small value of -0.00002
hours.
17

firms under recession is labor hoarding, which implies the maintenance of a certain
level of employment in firms to the furthest extent possible. In economic downturns of
the past, such a practice was common particularly when a negative shock wasconsidered temporary and firms reduced employees’ working hours in order to reduce
personnel costs. However, when the shock is predicted to be persistent and substantial,
firms in which the internal labor market has developed and firm specific skills havebeen accumulated can reduce employment. Under such circumstances, our empiricalexamination using micro data revealed that there was an increase in the number ofworking hours among employees of firms that greatly reduced the number of regular
employees since the retained employees were required to fulfill fixed duties that arenecessary for the maintenance of internal organization.
Furthermore, we also found two other reasons to explain the increase in number ofworking hours during the recession. The Japanese system of wages and employment
practices has been substantially in transition since the 1990s. The seniority-based wage
rule has weakened, and an increasing number of firms are employing theperformance-based one, thereby enlarging the wage disparity as compared to that in thepast. In this paper, we indicated that the working hours of male regular employees
tended to increase in firms where there has been a steady increase in the wage varianceon the basis of performance. In addition, the number of non-regular employees has
increased rapidly in Japan as well as in other developed countries. In this paper, wefound an increase in the number of working hours of Japanese male regular employees
who work in firms that drastically increased the ratio of non-regular workers.
In conclusion, two important remarks of these results must be noted. First, theeffect of the transitions in the wage and employment practices in Japan may not be
continuous but transient, as they occurred just in the beginning of the 2000s. For
example, the effect of increasing non-regular workers on the increase in the number ofworking hours disappeared in the latter half of the 2000s, as is evident from the resultsof our paper. According to Genda, Kuroda, and Ohta (2010a), the ratio of regular
employees who work for extremely long hours (over 60 hours per week) has decreased
since 2005, and this phenomenon was particularly prevalent among employees in theservice and production occupations. This is because non-regular employees such asdispatched workers were rapidly introduced in these occupations. 18 In our casual
observation, it appears that in period of economic recovery after 2005, firms chose to18

Until 2004, the Labor Dispatched Law prohibited manufacturing factories from using
dispatched production workers in Japan. Due to the deregulation in 2004, which permitted thefactories to hire these dispatched workers, the proportion of such workers has increased rapidly
in the industry.
18

increase such non-regular workers as a buffer for unexpected contingencies rather thanasking regular workers to increase overtime work. Further examination will be required
to study the long-term effect of including non-regular workers on regular working
conditions.
Second, it is also noteworthy to examine the number of working hours of female
employees. Genda, Kuroda, and Ohta (2010b) revealed the polarization of working
hours among female regular employees, while their average working hours tended tofall. Their study suggests that a certain amount of female regular employees also
increased the number of working hours from the late 1990s to the early 2000s, whileother female regular employees worked for shorter hours. Our tentative analysis
suggests that females who were employed in firms that introduced the meritocratic
performance-based wage system as well as those that underwent a change in theiremployment and wage policies drastically tended to increase working hours, which isfeature that we have observed for male employees. However, a detailed analysis isrequired to consider the trend of inequality of number of working hours among regularfemale employees in the future.

19

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21

Figure 1. Average weekly working hours of prime-aged regular male employees in
Japan
52

hours/week

%
6.0

51

5.0

50

4.0

49

3.0

48

2.0

*
47

1.0
the number of hours worked
the unemployment rate

46

0.0
1986

1988

1990

1992

1994

1996

1998

2000

2002

2004

2006

Sources: The Special Survey of the Labour Force Survey (1986–2001) and data obtained from thespecial questionnaire of the Labour Force Survey (2002–2007).
Notes: Prime-aged regular male employees exclude self-employed, part-time employees, non-regular
employees, and students. The unemployment rate is the national average for male employees.
* indicates the actual number of working hours in 1989 that are reported in the statistics. The
large drop in this year is due to taiso-no-rei (the ritual of the Showa emperor’s demise), which
took place during the last week of February 1989, when numerous Japanese workers took a
day off to offer condolences. Since this was a special occasion, we conducted a linear
interpolation from 1988 and 1990 in this figure.

22

Figure 2. Divergence in working hours among different groups of employees

104

2004
103

2004

2004

102

1988

101

2004

100

1988
99
98

1988
1988

97
96
95
30s/20s40s/20s

Univ./non-univ.

White-collar/
blue-collar

Notes: “30s/20s” and “40s/20s” indicate the average number of working hours of employees in their
30s and 40s respectively, when the average number of working hours of employees in their
20s equals 100. “Univ./Non-univ.” indicates the average number of working hours ofuniversity graduates when the average number of working hours of non-university graduates
equals 100. “White-collar/blue-collar” indicates the average number of working hours ofwhite-collar workers when the average number of working hours of blue-collar workers
equals 100. Further, “White-collar” includes professional and technical workers, managers
and officials, clerical and related workers, and sales workers. “Blue-collar” includes
protective service workers, workers in transportation and communication, production process
workers, and laborers.

23

Table 1. Summary Statistics

Age
Educational background high school and junior high school diploma
junior or technical college (2 years) diploma
university diploma or more
Firm size
less than 30 employees(the number of
30 to 499 employees
employees)
500 employees and overIndustry
Construction
Manufacturing
Transport and postal activites
Wholesale and retail trade
Finance, insurance, and real estate
Other service industries
Occupation
Professional and technical workers
Managers and officials
Clerical and related workers
Sales workers
Protective service workers
Workers in transport and communication
Production process workers
Labourers
Marrital status(married = 1)
Having a child(having a child less than 6 years old = 1)
Spouse's work status (wife working = 1)
Nomial monthly wage (contractual Cash Earnings; 1,000yen)
Regional unemployment rate (%)
Composition of age structure
Possible factors
changes in the no. of workers
ratio of non-regular workers
changes in the ratio of non-regular workers
probability of dismissal
wage dispersion
Sample sizes

1998-1999
34.980 (8.36)
0.592 (0.49)
0.098 (0.30)
0.308 (0.46)
0.267 (0.44)
0.382 (0.49)
0.351 (0.48)
0.147 (0.35)
0.315 (0.46)
0.099 (0.30)
0.196 (0.40)
0.047 (0.21)
0.196 (0.40)
0.147 (0.35)
0.010 (0.10)
0.135 (0.34)
0.192 (0.39)
0.048 (0.21)
0.062 (0.24)
0.356 (0.48)
0.049 (0.22)
0.603 (0.49)
0.213 (0.41)
0.300 (0.46)
319.758 (90.64)
5.070 (0.88)
0.919 (0.28)
1.632 (11.44)
19.096 (11.03)
18.706 (17.25)-10.445 (26.73)
0.236 (0.05)

2002-2004
34.949 (7.79)
0.534 (0.50)
0.126 (0.33)
0.337 (0.47)
0.272 (0.44)
0.403 (0.49)
0.325 (0.47)
0.134 (0.34)
0.306 (0.46)
0.127 (0.33)
0.202 (0.40)
0.041 (0.20)
0.189 (0.39)
0.146 (0.35)
0.012 (0.11)
0.133 (0.34)
0.197 (0.40)
0.053 (0.22)
0.055 (0.23)
0.355 (0.48)
0.048 (0.21)
0.602 (0.49)
0.243 (0.43)
0.299 (0.46)
311.006 (87.58)
6.279 (1.31)
0.934 (0.31)-3.361 (13.59)
23.634 (12.01)
24.639 (16.26)-14.995 (45.10)
0.241 (0.04)

2006-200735.343 (7.57)
0.500 (0.50)
0.131 (0.34)
0.365 (0.48)
0.255 (0.44)
0.407 (0.49)
0.338 (0.47)
0.122 (0.33)
0.305 (0.46)
0.151 (0.36)
0.199 (0.40)
0.043 (0.20)
0.180 (0.38)
0.154 (0.36)
0.013 (0.11)
0.137 (0.34)
0.188 (0.39)
0.057 (0.23)
0.054 (0.23)
0.349 (0.48)
0.048 (0.21)
0.605 (0.49)
0.248 (0.43)
0.307 (0.46)
316.029 (92.42)
5.008 (0.97)
0.927 (0.32)
1.800 (11.10)
25.505 (13.69)
7.604 (11.25)-16.901 (47.95)
0.271 (0.05)

21943

21396

12549

Note: Values given in parentheses denote standard deviation.

24

Table 2. Estimation results from weighted least squares

Age

Age^2
Educational background(base = high school and junior high deploma)
junior or technical college (2 years) diploma
university diploma or more

1998-1999
0.002(0.36)
0.000(-0.71)

2002-2004
0.011 (1.51)
0.000 (-1.41)

2006-2007
0.014 (1.24)
0.000 (-0.91)

0.025
0.022

(3.90) ***(3.46) ***

0.019
0.037

(2.76)(5.17)

***

0.012
0.002

(1.20)(0.15)

0.036 (4.47)-0.011 (-0.85)-0.052-0.026-0.021-0.007-0.058(-4.38) ***(-1.35)(-1.08)(-0.46)(-5.18) ***-0.0640.071-0.030-0.024-0.079

0.029
0.075
0.049
0.075
0.072
0.004
0.034
0.029
0.017
0.002
-0.0350.004-0.018

0.024
0.022

(3.13)(2.48)

***

0.005
0.001

(0.58)(0.07)(-7.48)(2.48)(-1.57)(-1.62)(-5.47)***-0.052-0.048-0.005-0.040-0.049(-5.76)(-2.45)(-0.25)(-2.68)(-2.47)***(4.02) ***(4.48) ***(7.93) ***(6.93) ***(6.52) ***(0.64)(3.66) ***0.033 (4.64)
0.036 (1.79)
0.048 (7.08)
0.083 (7.50)
0.097 (8.83)-0.002 (-0.31)
0.038 (3.49)***

0.026 (2.86)
0.052 (2.87)
0.046 (5.44)
0.045 (3.03)
0.098 (6.39)-0.004 (-0.46)
0.041 (3.12)***(5.32) ***(3.24) ***(0.44)(-1.38)(1.32)(-1.31)

0.035
0.011
0.000
-0.070-0.001-0.006

***

0.031
0.024
-0.010-0.054-0.021-0.037

***

***

***
**

Firm size (base = less than 30)
30 to 499 employees
500 employees and overIndustry (base = construction)
Manufacturing
Transport and postal activites
Wholesale and retail trade
Finance, insurance, and real estate
Other service industries

**

***

**
***
**

Occupation (base = clerical)
Professional and technical workers
Managers and officials
Sales workers
Protective service workers
Workers in transport and communication

Production process workers
Labourers
Other control variables
Marital status (married = 1)
Child (less than 6 years old = 1)
Spouse works (work = 1)
log real monthly wage
regional unemployment ratecomposition of age structure
Possible factors
changes in the no. of workers
ratio of non-regular workers
changes in the ratio of non-regular wkrs
probability of dismissal
wage dispersion

Constant
prefecture and cohort dummies

R2-adj.
Sample sizes

0.000(-0.24)0.001(2.08) **0.000(-0.60)0.000(2.48) **0.124(2.04) **3.822(32.60) ***yes
0.044621943(5.97)(2.02)(-0.06)(-2.52)(-0.10)(-0.44)

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

**
**

-0.004 (-4.47) ***0.003 (3.87) ***0.001 (1.97) **0.000 (-0.69)
0.208 (3.16) ***3.591 (26.08) ***yes
0.049521396(4.14)(3.47)(-1.55)(-1.93)(-1.81)(-2.61)

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

***
*
*
***

0.000 (0.31)
0.000 (-0.19)-0.001 (-1.75) *0.000 (-0.27)
0.125 (1.71) *3.746 (17.66) ***yes
0.0421
12549

Notes: Values in parentheses denote t-statistics. ***, **, and * denote statistical significance at the 1,
5, and 10 percent levels respectively.

25

Table 3. Estimation results from the Tobit model
Possible factors
changes in the no. of workers
ratio of non-regular workers
changes in the ratio of non-regular workers
probability of dismissal
wage dispersion

1998-1999
0.000 (-0.65)
0.002 (2.47)
0.000 (-0.73)
0.000 (2.60)
0.133 (2.13)

**

***
**

0.0819-7551.57
21943

Pseudo R2
Log likelihood
Sample sizes

2002-2004-0.004 (-5.37)
0.003 (4.61)
0.001 (2.69)
0.000 (-0.61)
0.238 (3.95)

***
***
***

***

0.0975-6586.30
21396

2006-2007
0.000 (0.80)
0.000 (-0.62)-0.001 (-1.72)
0.000 (-0.13)
0.156 (2.18)***

0.0942-3477.66
12549

Notes: Values given in parentheses denote t-statistics. ***, **, and * denote statistical significance atthe 1, 5, and 10 percent levels respectively. The same control variables as those in table 2
are used for this estimation.

Table 4. Estimation results from the Tobit model by age(1) 30s
Possible factors
changes in the no. of workers
ratio of non-regular workers
changes in the ratio of non-regular workers
probability of dismissal
wage dispersion

Pseudo R2
Log likelihood
Sample sizes

1998-1999-0.001 (-0.88)
0.002(1.67)
0.000(0.14)
0.000(0.84)
0.239(1.85)**

2002-2004-0.003 (-2.49)
0.004(3.11)
0.001(1.29)
0.000 (-0.61)
0.167(1.63)

0.0878-2772.56
8194

0.1137-2662.10
9013

1998-1999-0.001 (-1.40)
0.001(0.59)-0.001 (-1.88)-0.001 (-1.51)
0.111(1.03)

2002-2004-0.004 (-2.66)
0.003(2.17)
0.001(2.30)
0.000 (-0.03)
0.349(3.43)*****

2006-2007
0.001(0.87)
0.000 (-0.35)
0.000 (-0.67)
0.001(2.55)
0.189(1.66)***

0.0993-1570.8
5620(2) 40s
Possible factors
changes in the no. of workers
ratio of non-regular workers
changes in the ratio of non-regular workers
probability of dismissal
wage dispersion

Pseudo R2
Log likelihood
Sample sizes

0.0807-3068.68865*

0.0907-2454.54
7873

Notes: Same as Table 3.

26

***
**
**

***

2006-2007
0.002(2.40)-0.002 (-1.80)-0.001 (-1.65)
0.000 (-0.90)
0.287(2.32)
0.1474-1181.85
4731

**
*

**

Table 5. Estimation results from the Probit model
Possible factors
changes in the no. of workers
ratio of non-regular workers
changes in the ratio of non-regular workers
probability of dismissal
wage dispersion

1998-1999-0.001 (-1.91)
0.002 (2.30)
0.000 (0.37)
0.000 (-0.16)-0.053 (-0.75)
0.0450-6580.164
21943

Pseudo R2
Log likelihood
Sample sizes***

2002-2004-0.006 (-5.03)
0.005 (4.80)
0.001 (2.51)
0.000 (-0.36)
0.010 (0.11)

***
***
**

0.0418-8713.918
21396

2006-2007-0.001 (-1.39)
0.000 (0.26)
0.000 (-0.43)
0.000 (-1.05)
0.100 (1.00)
0.0445-4787.799
12549

Notes: Same as Table 3. The left-hand side variable takes 1 if an employee works for over 60 hours
per week, and 0 otherwise. The figures represent marginal effects.

Table 6. Estimated value of each factor that led to an increase in working hours
during the period 2002–2004
Possible factors
changes in the no. of workers
ratio of non-regular workers
changes in the ratio of non-regular workers
probability of dismissal
wage dispersion

0.686
0.485
0.150
0.035

Notes: The unit used is hours. The estimated values are calculated from the results obtained in Table
2.

27

Appendix Table. Robustness check (Tobit model)
Possible factors
changes in the no. of workers
ratio of non-regular workers
changes in the ratio of non-regular workers
probability of dismissal
wage dispersion

Pseudo R2
Log likelihood
Sample sizes

0.000

0.000
0.137

(-0.22)(2.46) **(2.18) **

0.000
0.002
0.000
0.135

0.0816-7554.63

0.0819-7551.00

Pseudo R2
Log likelihood
Sample sizes-0.001

0.000
0.249

(-2.96) ***(-1.44)(4.14) ***-0.003
0.003
0.000
0.232

0.096
-6597.55

Pseudo R2
Log likelihood
Sample sizes(1.70)*

0.0814-7556.10

2002-2004(-4.76) ***(3.91) ***
0.001
0.000
(-0.95)(3.85) ***
0.227

0.097
-6589.92

0.000
0.134

(2.49) **(2.15) **0.0815-7555.20(1.47)(-0.96)(3.77) ***0.0955-6601.30

0.000
0.239

(-1.42)(3.98) ***0.0954-6602.00

21396

Possible factors
changes in the no. of workers
ratio of non-regular workers
changes in the ratio of non-regular workers
probability of dismissal
wage dispersion(2.06) **(-1.00)21943

Possible factors
changes in the no. of workers
ratio of non-regular workers
changes in the ratio of non-regular workers
probability of dismissal
wage dispersion

1998-1999(-0.68)(2.37) **
0.001
0.000
(2.65) ***(2.16) **
0.105

0.000

0.000
0.163

(-0.11)(-0.18)(2.29) **

0.000
0.000
0.000
0.164

0.0938-3479.19

2006-2007(0.08)(-0.35)0.000-0.001(-0.18)(2.29) **0.157

0.0938-3479.128(2.20) **0.0941-3477.99
21396

Note: Same as Table 3.

(-0.25)(-1.52)
0.000
0.121

(-1.55)(1.74)

0.0926-3483.9*