Abstract
In recent years, sociologists have increasingly investigated the ways in which institutional or organizational features of the labor market constrain workers' mobility patterns throughout the economy. Building on this work, this article analyzes union effects on patterns of job mobility. It finds that the union effects vary by type of union and by type of job change, with industrial unions promoting the incidence of intrafirm occupation changes and craft unions decreasing the incidence of interoccupation moves. Apparently, unions operate to lend coherence and stability to careers by binding their members more closely to organizational and occupational structures.