“…Regarding the impact of external technology search strategies on EI (Ghisetti et al, 2015), we consider the breadth of knowledge sources as a control variable, spanning three external sources of information to control for the scope of other knowledge sources: (1) market sourcing, or information from suppliers, clients, competitors, consultants, commercial labs, private R&D institutes, and other firms in the sector; (2) institutional sourcing, including that from universities, other higher education institutions, and government and public research institutes; and (3) other sources, such as patents, databases, trade literature, or fairs. We assign a value of 1 for each source if that source is crucial 5 to the focal firm's innovation activities, and 0 otherwise.…”