This chapter examines various types of market studies and how they can be used to inform and design government policy. Market studies serve three important functions for a competition agency: (1) expanding the base of knowledge; (2) facilitating the preparation of reports about competitive conditions within and across commercial sectors; and (3) enabling the competition agency to engage in competition advocacy and to prepare recommendations for regulatory reform. A competition agency must anticipate strong political opposition and may have to select cautiously among controversial issues. The more effective the study is in redressing substantial monopoly power, the greater the political hazards it can pose to the agency. To confront these challenges, an agency must have a skilled research team, anticipate demands on resources, anticipate political risks and devise strategies for effective implementation. High-quality market analysis is a necessary ingredient for good policy making.