Explaining the evolution of pension structure and job tenure

Average and expected job tenure of workers has fallen significantly over the last two decades. Workers have also experienced a major shift in pension coverage. Traditional defined benefit pensions, designed to reward long tenure, have become steadily less common, while defined contribution pensions, which are largely portable, have spread. The link between job tenure and pension trends has not been closely examined, but it offers insights about both phenomena. This paper uses a contract-theoretic matching model with moral hazard to explain changes in both pension structure and job tenure; we discuss how a richer model with job-specific human capital subject to technology shocks would yield similar results. In our model, a decline in the value of existing jobs relative to new jobs reduces expected match duration and thus the appeal of DB pensions. We argue that these trends are linked to changes in the nature of new technologies. This explanation is consistent with observed trends in technological change, tenure, and pension structure. Our results suggest an additional consequence of technological progress that has not been closely studied.