Academic entrepreneurship. We measu

Academic entrepreneurship. We measured academic entrepreneurship using three indicators drawing on prior work (Blumenthal et al. 1997; Blumenthal et al. 2006; Walsh et al. 2007). First, we asked if respondents were involved in commercial activities in the two year period 2007 to 2008, including negotiations with industry, planning a new business, establishing a startup firm, development of new technologies for commercial purposes, or earning licensing income. We assigned respondents involved in at least one commercial activity avalue of one on a dummy variable (individuallevel commercial involvement ), zero otherwise(Campbell et al. 2002). Second, following Hong and Walsh (2009), we asked respondents to list up to seven recent collaborators. If at least one collaborator was from industry, we coded a dummy variable one (individual-level industry collaboration). Third, we asked respondents what proportion of their research funds were from industry. If industry funding was greater than zero, we coded a dummy variable one (individual-level industry funding ) (Campbell et al. 2002; Hong and Walsh 2009).10 We averaged these three individual-level measures at the field level to obtain measures of field-level academic entrepreneurship (field-level prevalence of commercial involvement, industry collaboration, , and industry funding , respectively).11