ANTITRUST ECONOMISTS scrutinize industries for monopoly power. They often testify in court cases whether mergers and other business actions will make industries less competitive. They evaluate government policies intended to promote competition and propose changes.

DEVELOPMENT ECONOMISTS study developing countries. They try to determine why some poor countries are growing fast and others are barely growing. They also evaluate programs intended to reduce poverty and improve incomes, health, and well-being in poor countries.

EDUCATION ECONOMISTS study the impact of education on life outcomes like employment, earnings, and health. They measure the costs and effectiveness of programs like pre-kindergarten, summer, and charter schools. They investigate the impact of teacher education, class size, and alternative teaching methods.

ENVIRONMENTAL ECONOMISTS study the interaction between economic activity and the environment. They evaluate the effectiveness of existing government programs intended to help the environment and design new ones.

HEALTH ECONOMISTS study the health care system. They investigate how incentives affect health care outcomes—who gets care, how much care they get, and the quality of that care. They evaluate the cost and effectiveness of alternative health care systems.

INTERNATIONAL ECONOMISTS study patterns of trade and investment between countries. They study how international trade affects jobs, incomes, and economic growth in the U.S. and other countries. They evaluate the effectiveness of international trade agreements and organizations like the World Trade Organization. They also evaluate alternative policies for setting exchange rates between countries' currencies.

LABOR ECONOMISTS study the employment conditions of workers: pay, benefits, hours, health and safety, risk of layoff, etc. They investigate government programs such as minimum wage laws, union laws, unemployment insurance, social security, food stamps, anti-discrimination laws, and job training to determine how much they help workers. Some testify in court about how much a particular worker would earn were it not for some mishap, such as an accident or a wrongful firing.

MACROECONOMISTS study economic growth, inflation, and recessions, seeking to understand their causes. Those working in business and government often produce forecasts of GDP, unemployment, inflation, and interest rates. Other macroeconomists study the effectiveness of government policies intended to promote economic growth or control business cycles.

PUBLIC ECONOMISTS study government programs and the tax systems that pay for them. They measure the effectiveness of government programs—defense, education, highways, poverty programs, social security, etc.—and the quality of government decision-making. They measure the impact of taxes on people's incentives to work and invest, economic growth, and inequality.