Estimating Gender Differences in Access to Jobs : Females Trapped at the Bottom of the Ladder

Firms are more productive on average in larger cities. Two explanations have been offered:agglomeration economies (larger cities promote interactions that increase productivity) and firmselection (larger cities toughen competition allowing only the most productive to survive). Todistinguish between them, we nest a generalised version of a seminal firm selection model and astandard model of agglomeration. Stronger selection in larger cities left-truncates the productivitydistribution whereas stronger agglomeration right-shifts and dilates the distribution. We assess therelative importance of agglomeration and firm selection using French establishment-level dataand a new quantile approach. Spatial productivity differences in France are mostly explained byagglomeration.