The Variety of Related Variety Studies: Opening the Black Box of Technological Relatedness via Analysis of Inter-firm R&D Cooperative Projects

The aim of this article is twofold. First, on the basis of a review of recent literature on related variety, it shows that there are not only differences between ex-ante and ex-post conceptualisations of relatedness, but also several striking methodological differences within this research stream. Therefore, it is argued, the growing number of studies on relatedness using different conceptualisations and methodologies can result in a “hollowing-out” of the original explanatory power of the concept. Second, this paper aims to open the black box of relatedness among industries by exploring one of the main channels through which the effects of relatedness can operate by simultaneous application of both ex-ante and ex-post approaches to measuring relatedness. In particular, joint R&D projects among companies represent a vigorous mechanism of knowledge exchange and mutual learning, but, as of yet, these studies have not been systematically linked to the concept of related variety. Our results prove that R&D collaboration according to technological distance is indeed far from random, but, contrary to our expectation, the results show that R&D collaboration occurs most frequently among unrelated companies. Thus, the search for partners in R&D projects seems to be driven by the novelty of knowledge rather than by probabilities of its comprehension. Conceptually, these findings suggest that in reality there might be various processes that require vastly different level of relatedness. This could lead to important policy implications as overreliance upon support for related industries might be misleading.