Who creates jobs? : estimating job creation rates at the firm level

This paper analyzes econometric models of the Davis, Haltiwanger and Schuh (1996) job creation rate. In line with the most recent job creation literature, we focus on employment-weighted OLS estimation. Our main theoretical result reveals that employment-weighted OLS estimation of DHS job creation rate models provides biased marginal effects estimates. The reason for this is that by definition, the error terms for entering and exiting firms are non-stochastic and non-zero. This violates the crucial mean independence assumption requiring that the conditional expectation of the errors is zero for all firms. Consequently, we argue that firm entries and exits should be analyzed with separate econometric models and propose alternative maximum likelihood estimators which are easy to implement. A small-scale Monte Carlo analysis and an empirical exercise using the population of Austrian firms point to the relevance of our analytical findings.