Incidence and Duration of Unemployment Spells: Implications on the Wage Differentials of Part-Time and Full-Time Workers

This article analyzes the extent to which incidence of unemployment and duration of unemployment spells affect the wage differentials between full-time and part-time workers. The estimation results of a sample selectivity bias–adjusted wage equation reveal that high incidences of unemployment are associated with low wages for both full-time and part-time workers. However, the reduction in wages due to incidence of unemployment is larger for full-time workers in high-paid jobs than for their part-time counterparts. Duration of unemployment spells affects full-time and part-time workers differently. In general, longer unemployment spells tend to increase the wages of full-time workers but tend to depress the wages of part-time workers. Although the probability of unemployment is not a factor in explaining the wage differential, the duration of unemployment accounts for a substantial portion (about 66.6% in full sample) of the wage differential that exists between full-time and part-time workers.     

Distributional assumptions and a test of the dual labor market hypothesis

Recent application of the switching regression model to allocate workers into the primary and secondary labor markets is considered to be the best solution to the classification problem of the empirical testing of the dual labor market theory. In such models, normality of the error terms is assumed. This paper adopts the switching regression model to test the dual labor market theory by assuming different distributions of the error terms. The test results strongly support the dual labor market theory regardless of the assumption one makes about the error terms. However, the results indicate that different distribution can lead to different percentage distributions of workers in the two segments. In particular, the normal distribution generates more workers in the primary segment than the non-normal distributions. Therefore, care must be taken not to generalize the type of industries or occupations that fall under the primary and secondary segments. First version received: October 2000/Final version received: March 2002 RID="*" ID="*"  I would like to thank Kevin Lang, Robert Marshall, and two anonymous referees for their helpful comments. I am grateful for comments received from the session participants of the Western Economic Association International Conference, San Francisco, CA, June 28–July 2, 1996, and the Midwest Economic Association Conference, Kansas City, 1997. I thank George Bonney, the Chief Statistician of Fox Chase Cancer Center, Philadelphia for his comments. Any remaining errors are my responsibility. I gratefully acknowledge financial support from Penn State Research and Development Grant, 1995.     

Learning-by-doing and input demand of a rate-of-return regulated firm

The significance of learning by doing to input demand of a cost-minimizing rate-of-return-regulated firm is examined. Using a panel data, the results indicate that the firm's cost and input demand decisions are both influenced by learning-by-doing. The firm's cost and the rate-base (capital) input requirements decline as learning-by-doing measured by cumulative production expands. However, LBD may have different effects on the non-rate-base inputs (labor and fuel) considered in this study. While LBD ambiguously reduces fuel usage, it moderately increases labor employment. In addition to changing input intensity, LBD also influences returns to scale and elasticity of substitution.     

Intertemporal consumer behaviour in developing countries

This paper explores aggregate consumption behaviour in four developing countries under the assumption that consumers' planning horizons do not extend over their expected lifetime. Under certain conditions, the resulting ‘moving planning horizon model’ suggests that changes in current income would exert considerably more influence over current consumer spending than is predicted by forward-looking theories of consumption which typically assume that consumers' planning horizons coincide with expected lifetime. Estimation of the model for the group of developing countries provides empirical support for the role of changes in current income in influencing the consumption process. The results also reveal that consumers are relatively short-sighted sinced the length of the planning period of consumers ranges from just over ten months. An important implication of these findings is that policy measures can be effective not only if they influence consumers' permanent incomes but also if they affect changes in current income.     

Black–white wage differentials: duration and probability unemployment effects in a multiple of sample selection bias model

The extent to which probability and duration of unemployment affect the black–white wage differentials is examined in this paper. The paper simultaneously incorporates in the wage equation the multiple sample selection bias that occurs as a result of individuals’ propensity to be in the labor force, and the firm’s hiring decisions. The results reveal a substantial contribution of the duration of unemployment variable to the black–white wage differential, but a small portion of the differential is explained by the probability of unemployment. The results also indicate a sizeable difference between the contribution of the duration of unemployment variable to the male’s wage differentials (26%) and to the female’s (35%). The study finds that an individual’s labor force decision as well as a firm’s hiring decision are important in the wage determination process and that failure to account for the sample selectivity bias due to these two decisions will result in either underestimating or overestimating the wage differentials between black and white workers. At the macro level, the results seem to suggest that promotion of racial wage equality should be associated with policies that will minimize blacks’ incidence of unemployment and duration of unemployment spells.     

Incidence and duration of unemployment spells: Implications for the male–female wage differentials

We demonstrate in this paper that the incidence of unemployment and duration of unemployment spells affect the male–female gender wage differential. The results indicate that after controlling for sample selectivity bias in the wage equation, the incidence of unemployment and duration of unemployment spells account for about 14.2% and 39.6%, respectively, of the wage differential that exists between males and females. We observed that while the duration of unemployment accounts for a substantial portion of the wage differential in both the service (48.8%) and the manufacturing (17.0%) sectors, the impacts of the incidence of unemployment and duration of unemployment spells variables on the wage differential are rather small in the service (0.07%) and the manufacturing (1.6%) sectors. Also, high incidence of unemployments is associated with low wages for males and females in all samples. In contrast, longer durations of unemployment spells tend to increase males’ wages and decrease females’ wages in the full and service sector samples. At the macro level, the results seem to suggest that promotion of gender wage equality should be associated with policies that will minimize the female's incidence of unemployment and duration of unemployment spells.     

Productivity Growth and Input Demand: The Effect of Learning by Doing in a Gold Mining Firm in a Developing Economy

This paper analyzes the effect of learning by doing (LBD) on the firm’s productivity growth and its input demand decisions. The results indicate that LBD is an important determinant of the firm’s productivity growth. The contribution of LBD to the firm’s productivity growth is about 5.6%. Another observation is that LBD has a decreasing effect on the firm’s cost of production – a finding which is consistent with the results of many studies. Also, an increase in LBD measured by cumulative production increases the firm’s demand for capital, and decreases the firm’s demand for labor. Lastly, LBD has a significant effect on the firm’s elasticity of scale. A fundamental message derived from the study is the confirmation that the firms should invest in more large capital equipment, embark on new processing techniques, and create an environment that is conducive to on-the-job learning.     

The Impact of Income Taxation on the Labor Supply of Part-time and Full-time Workers

This paper estimates the effect of income taxation on the labor supply of part-time and full-time workers in the United States. Using a model that incorporates the endogeneity of the net wage rate and the virtual income, and correcting for self-selection into part-time and full-time jobs, the results indicate that part-time workers are relatively more responsive to changes in income tax than full-time workers. Estimated wage elasticities are relatively larger for part-time than for full-time workers.The simulation results indicate that income tax has a disincentive effect on both part-time and full-time workers, with part-time and full-time workers reducing their labor supply by 0.87 and 0.58 hours, respectively, if a 5% tax is imposed. However, the percentage reduction in hours of work is very small, and a tax policy may have little effect on the labor supply of workers.The results seem to suggest that female and black part-time workers are more likely to drop out of the labor force at higher levels of income tax. It also tests the hypothesis that the labor supply behavior of parttime and full-time workers differs.The test results indicate that the determinants of the labor supply of part-time workers are different from those of full-time workers. It is noted that there is a significant difference between the labor supply of male part-time and female parttime workers, as well as between the black part-time and white part-time workers. In order to reduce voluntary unemployment in market activities among married females and blacks, the government can encourage part-time work by sponsoring legislation or instituting a scheme that will allow part-time workers to pay relatively less in payroll taxes.     

Interindustry part-time and full-time wage differentials: regional and national analysis

This paper provides more evidence that the wage differential is far smaller than is suggested by simple comparison of gross wages of full-time and part-time workers. It is noted that to obtain a more reasonable measure of the full-time and part-time wage differential, it is necessary to adjust for differences in workers' characteristics, labour market conditions and sample selection. It is found that, in general, full-time and part-time workers exhibit different personal characteristics. In particular, full-time workers possess more human capital and experience than part-timers. Also, labour market conditions such as unions and pension plans favour full-timers. These differences may partly account for the wage disparity between full-time and part-time workers. It was noted that the nonrandomness of the workers into full-time and part-time jobs influences the wage determination of both full-time and part-time workers. The results indicate that the adjustment of the wage equations to reflect the above mentioned differences reduces the national wage differential between full-time and part-time workers by 10%. The reduction is even larger across regions and industries. Another finding was that the wage determination processes between full-time and part-time workers do differ.     

Black–White Wage Differentials in a Multiple Sample Selection Bias Model

This paper simultaneously incorporates two sources of selection bias in the black-white wage equations. It demonstrates that the biases due to an individual’s propensity to be in the labor force and the firm’s hiring practices are important in determining the black–white wage differential and failure to account for both biases will result in inaccurate estimation of the black–white wage differential. We found that adjusting for double selection bias in the wage equation, the black–white female wage gap is 26% larger than the black–white male wage gap, and 12.1% larger when we adjust for a single selection bias. The results seem to suggest that at the macro level, the enforcement of policies related to racial issues in the labor market will likely lead to a reduction in the black–white wage gap.