• inventor;
  • specialization;
  • technological scope;
  • resource;
  • organization

Firms with different scope of technologies experience different firm growth. Understanding such heterogeneity requires knowing not only what drives technologies' scope but also why these drivers remain different across firms. I propose inventor specialization as a driver of technologies' scope: firms with more specialized inventors create narrower scope technologies. I also propose that these narrower scope technologies themselves in turn induce these firms' inventors to remain more specialized. I empirically demonstrate this two-way interrelationship in the U.S. communication equipment industry using policy shocks as natural experiments and a new measure of scope. This interrelationship has important implications for why resources and organization appear isomorphic within a firm but heterogeneous across firms. t © 2013 John Wiley & Sons, Ltd.