"It is well-known that 50% or more of all jobs are obtained through informal channels i.e. connections to family or friends. As well, statistical studies show that observable individual factors account for only about 50% of the very wide variation in earnings. We seek to explain these two facts...

This paper presents a model in which mismatch employment arises in a constrained efficient equilibrium. In the decentralized economy, however, mismatch gives rise to a congestion externality whereby heterogeneous job seekers fail to internalize how their individual actions affect the labor...