What you know or who you know? Human capital and social capital as determinants of individual performance

Is it who you know or what you know that helps you perform at work? Substantial bodies of research suggest that social capital and human capital are each important resources for getting ahead. Further, social and human capital operate at the same time and interact with each other, yet very few studies explicitly examine the two together, and those that do have conflicting findings. In this study, I argue that the inconsistency in findings results from of lack of conceptual clarity around the mechanisms underlying social and human capital. I highlight similarities and differences in the resources comprising social and human capital, and I focus on resource heterogeneity as an important common mechanism. By concentrating attention on heterogeneity from both human and social sources, I can examine some of the ways the underlying resources interact and test for joint effects. In addition, I focus on the outcome of job performance; an important intermediate outcome between social and human capital resources and the more commonly studied outcomes like wages or promotions. To address these issues, I conducted a field study of productivity and innovative performance of Claims Adjusters in a major U.S. insurance firm. I find that work experience heterogeneity has a positive relationship with innovativeness, but a negative relationship with productivity. In contrast, social network heterogeneity is a more adaptable resource that contributes to both aspects of performance. However, there are differences in contributions of different forms of social network heterogeneity. The content of social ties drives the positive effect for innovativeness, while the positive effect on productivity is driven by the characteristics of the network contacts. I also find that human and social resources, when defined in terms of heterogeneity, interact in a negative way with respect to job performance: that their usefulness overlaps