A study examined the role of worker-specific skills, occupational skill requirements, and job working conditions on the part-time/full-time wage differential. Analysis of research found that part-time employment was concentrated among jobs requiring a lower skill level and that measurable personal and location characteristics accounted for a large portion of wage differences. Relatively standard log wage regressions were estimated; wages for part- and full-time workers with the same measured characteristics were compared; part-and full-time workers with similar characteristics and working in similar jobs were compared; and longitudinal analysis measured wage changes for individuals as they moved from part- to full-time work, or vice versa. Data were from the Current Population Survey Outgoing Rotation Group earnings files for January 1989-December 1997. Analysis showed about two-thirds of the part-time wage disadvantage can be accounted for by measurable differences in workers and jobs. Much of the remaining differential reflected unmeasured worker-specific skills and tastes, as captured through longitudinal analysis. Most of the rather sizable part-time wage disadvantage results from differences between workers' job characteristics, preferences, and most importantly, accumulated worker skills. (Appendixes contain construction of the longitudinal database, 17 endnotes, 35 references, 7 tables, and 4 figures.) (YLB)