Related Diversification: A Critical Reflection of Relatedness and the Diversification-Performance Linkage

The linkage between diversification and performance has puzzled scholars for decades. A vast amount of empirical studies, together with the help of meta-analyses condensing diverse results, established a widely shared understanding that related diversification leads to superior firm performance. The main rationale for this finding is that relatedness within a company’s portfolio of businesses allows the company to achieve synergies by sharing or transferring resources. Although the predominant importance of related diversification seems generally accepted, scholars raise severe concerns about our ability to precisely define and measure relatedness. In most studies, traditional measures of diversification such as the Berry index are used, which assess relatedness from a product/market perspective. However, these measures face strong criticisms for their low degree of content validity. So if we doubt our understanding of relatedness, how can we agree on the performance effect of related diversification? To reassure our understanding of the diversification-performance linkage, this study critically reflects upon the underlying phenomenon of relatedness. By compiling and evaluating the different perspectives of relatedness with their heterogeneous conceptualizations and measures, this study supports the view that the multi-facetted nature of relatedness can only be captured inadequately so far. Moreover, most prior work mainly focuses on synergy potential rather than on the realization of synergies, thereby neglecting a mechanism that may have an important bearing on the performance effects of diversification.