This Chapter provides a survey of the economics literature on multi-sided platforms with particular focus on competition policy issues, including market definition, mergers, monopolization, and coordinated behavior. It provides a survey of the general industrial organization theory of...

Two-sided platforms (2SPs) cater to two or more distinct groups of customers, facilitating value-creating interactions between them. The village market and the village matchmaker were 2SPs; eBay and Match.com are more recent examples. Other examples include payment card systems, magazines,...

Competition in many important industries centers on investment in intellectual property. Firms engage in dynamic, Schumpeterian competition for the market, through sequential winner-take-all races to produce drastic innovations, rather than through static price/output competition in the market....

U.S. v. Microsoft and the related state suit filed in 1998 appear finally to have concluded. In a unanimous en banc decision issued in late June 2004, the D.C. Circuit Court of Appeals rejected challenges to the remedies approved by the District Court in November 2002. The wave of follow-on...

A planner sets a lump sum transfer and a linear tax on labor income in an economy with incomplete markets, heterogeneous agents, and aggregate shocks. The planner's concerns about redistribution impart a welfare cost to fluctuating transfers. The distribution of net asset holdings across agents...

If health service delivery is poorly managed, then increases in inputs or ability may not translate into gains in quality. However, little is known about how to increase managerial capital to generate persistent improvements in quality. We present results from a randomized field experiment in 80...

We study optimal monetary and fiscal policy in a model with heterogeneous agents, incomplete markets, and nominal rigidities. We develop numerical techniques to approximate Ramsey plans and apply them to a calibrated economy to compute optimal responses of nominal interest rates and labor tax...

Two decades have passed since the Clean Air Act Amendments of 1990 launched a grand experiment in market-based environmental policy: the SO2 cap-and-trade system. That system performed well but created four striking ironies. First, this system was put in place to curb acid rain, but the main...

Government subsidies have driven rapid growth in U.S. wind and solar generation. Using data on hourly outputs and prices for 25 wind and nine solar generating plants, some results of those subsidies are studied in detail: the value of these plants' outputs, the variability of output at plant and...

The U.S. Clean Air Act, passed in 1970 with strong bipartisan support, was the first environmental law to give the Federal government a serious regulatory role, established the architecture of the U.S. air pollution control system, and became a model for subsequent environmental laws in the...