Why do part-time workers earn less? The role of worker and job skills

Part-time workers receive considerably lower hourly earnings than do full-time workers. Using Current Population Survey earnings files for September 1995 through December 2002, the author finds that measurable worker and job characteristics, including occupational skill requirements, account for much of the part-time penalty. Longitudinal analysis of the data indicates that much of the remaining gap reflects worker heterogeneity, evidenced by small wage gains and losses among workers switching between part-time and full-time jobs. The lower skills of part-time than full-time workers result primarily from limited work experience and accumulation of human capital. Little evidence can be found of a large wage gap between part-time and full-time women. A part-time wage penalty is found for men, but men account for less than one-third of total part-time employment.