Joseph Stiglitz helped create a new branch of economics, "The Economics of Information," exploring the consequences of information asymmetries and pioneering such pivotal concepts as adverse selection and moral hazard, which have now become standard tools not only of theorists, but of policy analysts. He has made major contributions to macro-economics and monetary theory, to development economics and trade theory, to public and corporate finance, to the theories of industrial organization and rural organization, and to the theories of welfare economics and of income and wealth distribution. In the 1980s, he helped revive interest in the economics of R&D. His work has helped explain the circumstances in which markets do not work well, and how selective government intervention can improve their performance.