In this study we have tried to answer the questions ofwhether and how it is possible to explain differences in effects of "crowding out" between segments of the labor market and between the men and women within those segments. Crowding out is defined as a situation in which highly educated employees get jobs that were held by lower educated employees. There are several important reasons to pose these questions. First, there are contradictions in current research about effects of crowding out. Even when the same data are used, researchers have arrived at different contradictory conclusions. These contradictions primarily result from differences in theories that are used and models that are tested. Second, the welldocumented differences in the allocation of employees over jobs between segments of the labor market is also likely to cause differences in effects of crowding out between segments, and little attention has been paid to this possibility. Finally, the well-documented differences in the allocation of men and women to jobs and segments is also likely to cause differences in effects of crowding out on men and women. .