1. Social capital refers to the benefits obtained from social networks and relationships. Structural holes refer to weak connections between different groups in a social network. 2. Individuals who bridge structural holes gain competitive advantages from access to non-redundant information and control over third-party relationships. This "structural hole hypothesis" has received empirical support. 3. Dense networks alone do not improve performance. However, closure within groups helps realize the added value from brokerage between groups. Social capital is maximized when networks have both structural holes and closure.

1. The Network Structure of Social Capital Ronald Burt 2000 A presentation by Mikhail Dubov Ruconomics.com

2. Social capital metaphor Derived from the presumption that social context matters for individual beliefs and behavior. Complement to human capital. Broad agreement: a kind of capital that can create for certain individuals or groups a competitive advantage in pursuing their ends .

3. Network models of markets How do networks affect competition? Information is problematic. Typically circulates within groups before it will circulate between groups. Diffusion of information may take time. Networks affect the markets through providing competitive advantage in information exchange.

4. Social capital of structural holes Structural holes are the weak connections between different groups. Holes create competitive advantage for individuals whose relationships span the holes. Information benefit : Holes are gaps between nonredundant sources of information. Nonredundant contacts offer information that is more additive than overlapping. Control benefit : Better-connected people benefit disproportionately from the holes by having control over third-party relationships.

5. Hole hypothesis Structural holes affect the degree of economic success of the society. Encourage entrepreneurship. Improve the coordination. Reduce costs relative to bureaucratic alternative. Speed the adjustment to equilibrium. Overall, structural holes allow to increase returns to human capital.

6. Empirical evidence Empirical evidence supports the hypothesis. Lab experiments: resources accumulate in people with exclusive connections. Census data: producer profit margins increase with structural holes in network of transactions. Archival and survey data : career advantages of having a contact network rich in structural holes. Holes encourage learning and creativity. Still unclear on entrepreneurship.

7. Closure argument Evidence from Chicago State University:

8. Integration with network closure argument Empirical evidence suggests that dense networks do not affect performance. Consistent with hole hypothesis. Contradiction with Coleman’s theory that dense networks are the source of social capital ( closure argument ). Rather than rejecting closure altogether we can try to integrate it into the theory. Brokerage is the source of added value but closures help realize this value.

9. Integration: profits Burt ( 1992 ); Burt et al. ( 1999 ) study census data on industry profits. Profit margins decrease with network constraint within the industry (internal constraint is measured as the extent to which output is spread among different producers) Profit margins also decrease with constraint beyond industry (external constraint measured as the extent to which producers have few independent suppliers and customers)

10. Empirical evidence of integration Social capital matters more for managers with fewer peers.

11. Integration: team performance External constraint – aggregate network constraint in member networks beyond the team. (brokerage) Internal constraint – network constraint of structural wholes within the team. (closure) Managers with a network rich in social capital (low external constraint) are promoted very early, while those with mostly redundant contacts are promoted very late. However, when there is poor communication and coordination within a team, the team can be expected to perform poorly .

12. Conclusions The closure argument describes how dense or hierarchical networks lower the risk associated with transaction and trust, which is associated with performance. The hole argument describes how brokerage creates opportunities to add value, which determined performance. The evidence (by Burt) justifies expanding the whole argument to include closure as an aspect of social capital enabling a group to act to benefit from the structural holes to which group members have access. Otherwise the evidence entirely supports holes over closure.