Research and teaching
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Jesper B. Sørensen and Olav Sorenson

We examine the relationship between income inequality and corporate demography in regional labor markets and specify two mechanisms through which the number and diversity of employers in a labor market affect wage dispersion. Vertical differentiation, or variation in the ability of organizations of a particular kind to benefit from labor inputs, amplifies inequality through quality sorting, as the most productive employees in a particular domain pair with the most productive employers. Increasing horizontal differentiation—variation in the kinds of organizations—reduces inequality as individuals can more easily find firms interested in their distinctive attributes and talents. Our analysis of Danish census data provides support for each thesis. Increased numbers of organizations operating within an industry in a region, a proxy for vertical differentiation, increases wage dispersion in that industry-region. Variation in wages, however, declines with increased horizontal differentiation among employers; this is measured by the diversity of industries offering employment within a region and the variance in firm sizes in an industry-region.

American Sociological Review, 72 (2007): 766-783

Michael D. Ryall and Olav Sorenson

The broker profits by intermediating between two (or more) parties. Using a biform game, we examine whether such a position can confer a competitive advantage, as well as whether any such advantage could persist if actors formed relations strategically. Our analysis reveals that, if one considers exogenous the relations between actors, brokers can enjoy an advantage but only if (1) they do not face substitutes either for the connections they offer or the value they can create, (2) they intermediate more than two parties, and (3) interdependence does not lock them into a particular pattern of exchange. If, on the other hand, one allows actors to form relations on the basis of their expectations of the future value of those relations, then profitable positions of intermediation only arise under strict assumptions of unilateral action. We discuss the implications of our analysis for firm strategy and empirical research.

Management Science, 53 (2007): 566-583

Olav Sorenson and Jasjit Singh

Although prior empirical research has established an association between science and the widespread diffusion of knowledge, the exact mechanism(s) through which science catalyses information flow remains somewhat ambiguous. This paper investigates whether the knowledge diffusion associated with science-based innovation stems from the norm of openness and incentives for publication, or whether scientists maintain more extensive and dispersed social networks that facilitate the dissemination of tacit knowledge. Our analysis supports the first mechanism: we track the movement of knowledge with patent citations, and find that science-based innovations diffuse more rapidly and widely, even after controlling for the underlying social networks of researchers as measured using information on prior collaborations. We also find that publication and social networks act as substitutes in the diffusion of knowledge.

Industry and Innovation, 14 (2007): 219-238

Olav Sorenson and David M. Waguespack

This study uses data on the U.S. film industry from 1982 to 2001 to analyze the effects on box office performance of prior relationships between film producers and distributors. In contrast to prior studies, which have appeared to find performance benefits to both buyers and sellers when exchange occurs embedded within existing social relations, we propose that the apparent mutual advantages of embedded exchange can also emerge from endogenous behavior that benefits one party at the expense of the other: actors offer better terms of trade and allocate more resources to transactions embedded within existing social relations, thereby contributing to the ostensible advantages of such exchange patterns. Findings show that not only do distributors exhibit a preference for carrying films involving key personnel with whom they had prior exchange relations, but also they tend to favor these films when allocating scarce resources (opening dates and promotion effort). After controlling for the effects of these decisions, films with deeper prior relations to the distributor perform worse at the box office. The results suggest that, rather than benefiting from repeated exchange, distributors overallocate scarce resources to these prior exchange partners, enacting a self-confirming dynamic.

Administrative Science Quarterly, 51 (2006), 560-589

Olav Sorenson, Susan McEvily, Charlotte Rongrong Ren, and Raja Roy

Although strategy research typically regards firm scope as a positional characteristic associated with performance differences, we propose that broad contemporary scope also provides insight into the routines that govern firm behavior. To attain broad scope, firms must repeatedly explore outside the boundaries of their current niche. Firms with broad niches therefore operate under a set of routines that repeatedly propel them into new market segments, expanding their niche. These niche expansions, however, involve risky organizational changes, behavior that disadvantages generalists relative to specialists, despite the positional value of broad scope. Empirical analyses of machine tool manufacturers and computer workstation manufacturers support this conjecture: (i) generalists introduce new products at a higher than optimal rate, thereby increasing their exit rates; and (ii) generalists also more frequently launch new models with novel features or targeted at new consumer segments rather than improving only incrementally on existing products, further accelerating their odds of failure. After adjusting for these behavioral differences, broad niche widths reduce exit rates, suggesting that they provide positional advantages. The paper discusses how this phenomenon may help to explain the diversification and multi-nationality discounts.

Strategic Management Journal, 27 (2006): 915-936

Link to workstation data at FIVE Project

Olav Sorenson, Jan W. Rivkin, and Lee Fleming

Because knowledge plays an important role in the creation of wealth, economic actors often wish to skew the flow of knowledge in their favor. We ask, when will an actor socially close to the source of some knowledge have the greatest advantage over distant actors in receiving and building on the knowledge? Marrying a social network perspective with a view of knowledge transfer as a search process, we argue that the value of social proximity to the knowledge source depends crucially on the nature of the knowledge at hand. Simple knowledge diffuses equally to close and distant actors because distant recipients with poor connections to the source of the knowledge can compensate for their limited access by means of unaided local search. Complex knowledge resists diffusion even within the social circles in which it originated. With knowledge of moderate complexity, however, high-fidelity transmission along social networks combined with local search allows socially proximate recipients to receive and extend knowledge generated elsewhere, while interdependencies stymie more distant recipients who rely heavily on unaided search. To test this hypothesis, we examine patent data and compare citation rates across proximate and distant actors on three dimensions: (1) the inventor collaboration network; (2) firm membership; and (3) geography. We find robust support for the proposition that socially proximate actors have the greatest advantage over distant actors for knowledge of moderate complexity. We discuss the implications of our findings for the distribution of intra-industry profits, the geographic agglomeration of industries, the design of social networks within firms, and the modularization of technologies.

Research Policy, 35 (2006): 994-1017

Giacomo Negro and Olav Sorenson

We investigate the competitive consequence of vertical integration on organizational performance using a comprehensive dataset of U.S. motion picture production companies, which includes information on their vertical scope and competitive overlaps. Vertical integration appears to change the dynamics of competition in two ways: (i) it buffers the vertically integrated firms from environmental dependence and (ii) it intensifies competition among non-integrated organizations. In contrast to the existing literature, our results suggest that vertical integration has implications well beyond both the level of the individual transaction and even the internal efficiency of the integrated firm.

Advances in Strategic Management, 23 (2006): 367-403

Olav Sorenson and Lee Fleming

Scientists, social scientists and politicians frequently credit basic science with stimulating technological innovation, and with it economic growth. Despite a substantial body of research investigating this general relationship, relatively little empirical attention has been given to understanding the mechanisms that might generate this linkage. This paper considers whether more rapid diffusion of knowledge, brought about by the norm of publication, might account for part of this effect. We identify the importance of publication by comparing the patterns of citations from future patents to three groups of focal patents: (i) those that reference scientific (peer-reviewed) publications, (ii) those that reference commercial (non-scientific) publications; and (iii) those that reference neither. Our analyses strongly implicate publication as an important mechanism for accelerating the rate of technological innovation: Patents that reference published material, whether peer-reviewed or not, receive more citations, primarily because their influence diffuses faster in time and space.

Research Policy, 33 (2004): 1615-1634

Lee Fleming and Olav Sorenson

A large body of work argues that scientific research increases the rate of technological advance, and with it economic growth. The precise mechanism through which science accelerates the rate of invention, however, remains an open question. Conceptualizing invention as a combinatorial search process, this paper argues that science alters inventors’ search processes, by leading them more directly to useful combinations, eliminating fruitless paths of research, and motivating them to continue even in the face of negative feedback. These mechanisms prove most useful when inventors attempt to combine highly coupled components; therefore, the value of scientific research to invention varies systematically across applications. Empirical analyses of patent data support this thesis.

Strategic Management Journal, 25 (2004): 909-928

William P. Barnett, Aimee-Noelle Swanson, and Olav Sorenson

We discuss the creation of organizations and their survival as distinct selection processes, and consider the significance of their divergence. In particular, to understand the implications of entrepreneurial booms, we propose the possibility of asymmetric selection, where entry selection and exit selection differ from each other in strength. An observed increase in founding rates hence may reveal a decline in the selection threshold for entry—implying lower average fitness among boom-time entrants. When such an expansion occurs, organizations born during these periods of heightened entry should suffer higher failure rates in the fitness threshold required for survival remains stable or becomes more stringent. We also discuss other processes that might educe founding waves, and explain the different implications of these accounts for our empirical model. Estimates of the model support our theory of asymmetric selection in two out of three markets using a comprehensive dataset describing organizations in the U.S. computer industry.

Industrial and Corporate Change, 12 (2003): 673-695