We examine the generalizability of internally valid estimates of causal effects in a fixed population over time when that population is subject to aggregate shocks. This temporal external validity is shown to depend upon the distribution of the aggregate shocks and the interaction between these...

Based on German data between 1999 and 2007, we analyze the growth factors of SMEs and contrast them with those of large firms. Differences show up both in balance sheet and employment growth. While we confirm earlier results on inherent growth structures and the influence of firm age, we derive...