Which Stars Should You Reach For? Human Capital Spillovers of Star Scientists
Alexander Oettl
Rotman School of Management, University of Toronto
Human capital has long been recognized as a crucial input of economic growth. Indeed, Romer (1990) identifies externalities arising from human capital as key conditions for endogenous growth. Likewise, firms largely rely on human capital to develop both capabilities and competitive advantages. However, not all human capital is equal; the economic output of human capital is largely skewed, whereby the top producers generate disproportionately large levels of output. Consequently, two large streams of research have emerged. The first examines the role of human capital externalities, primarily in the fields of labor and education economics, while the second examines the performance effects of human capital in the right tail of the distribution (star scientists). Conspicuously absent from the literature, however, is the examination of the human capital externalities from these star scientists.
My dissertation attempts to build upon these streams of research by answering two key questions. First, to what extent do star scientists provide greater spillovers than non-star scientists? And second, are non-star scientist human capital externalities more mispriced than star scientists' externalities? A proper understanding of these effects and mechanisms has large implications for numerous literatures including collaboration networks, learning by hiring and the management of innovation.
To address these questions I build upon the current conceptualization of star scientists (stars with high personal productivity) by adding an additional dimension: sharing productivity. Using citation weighted publication counts to capture personal productivity and peer-reviewed journal acknowledgement counts to capture sharing productivity, I am able to identify scientists that have high personal productivity, but may or may not have high sharing productivity, and vice versa. In doing so, I am able to examine collaborator productivity as a function of star scientist type. For tractability I focus my analysis on economists. My variables of interest are generated from academic paper data from the top 30 economics journals and acknowledgement data from the American Economic Review and the Journal of Political Economy between the years of 1998 and 2007.