“…Specifically, the productivity premium increases as the share of output exported increases, but at a decreasing rate. Fourth, there is a growing body of evidence to suggest a further increase in productivity following entry, albeit for specific firms or time periods, see for example Kraay (1999), Castellani (2002), Baldwin and Gu (2004), Blalock and Gertler (2004), Van Biesbroeck (2003) and Girma et al (2004). These report second-order productivity effects, which could be due to learning, as in the Clerides et al (1998) model or scale effects as in Medin (2003).…”