This chapter reviews the recent debate about the role of social capital in economics. We argue that all the difficulties this concept has encountered in economics are due to a vague and excessively broad definition. For this reason, we restrict social capital to the set of values and beliefs...

The 'friendship paradox' (Feld1991) refers to the fact that, on average, people have strictly fewer friends than their friends have. I show that this over-sampling of the most popular people amplifies behaviors that involve complementarities. People with more friends experience greater...