"This paper reviews the recent theoretical literature on heterogeneous firms and trade, which emphasizes firm selection into international markets and reallocations of resources across firms. We discuss the empirical challenges that motivated this research and its relationship to traditional...

Empirical investigations with enterprise level data from official statistics often use the average wage as a proxy variable for the qualification of the workforce, mostly due to the lack of detailed information on the qualification of the employees. This paper uses unique newly available data...