Identification of Job Lock and Inefficient Labor Market Mobility

The common practice of linking employment with certain fringe benefits, notably health insurance, has long been thought to impede labor market mobility, thereby producing a phenomenon called job lock. A sizable literature has developed theoretical frameworks for how job lock impacts the labor market and empirically estimated the magnitudes of these effects. However, most empirical studies rely on identification strategies that do not separately identify productivity enhancing from productivity reducing labor market mobility. This article develops a simple theoretical framework showing how prior identification strategies confound both types of mobility and outlines conditions where productivity reducing mobility is of greatest concern.