Although we often mention who the leaders are when describing particular political parties, ruling groups, coalitions, administrations, terrorist groups, independence movements, and protest groups, little effort has gone into exploring why leadership might matter in understanding the decisions...

Social networks are typically constructed around an explicit and well-defined relationship among individuals. In this paper, we describe another class of social networks, known as Implicit Affinity Networks (IANs), where links are implicit in the patterns of natural affinities among individuals....

Have the idle rich replaced the working rich at the top of the U.S. income distribution? Using tax data linking 11 million firms to their owners, this paper finds that entrepreneurs who actively manage their firms are key for top income inequality. Most top income is non-wage income, a primary...

How important is human capital at the top of the U.S. income distribution? A primary source of top income is private “pass-through” business profit, which can include entrepreneurial labor income for tax reasons. This paper asks whether top pass-through profit mostly reflects human capital,...