Robert Emerson Lucas Jr. (born September 15, 1937) is an American economist at the University of Chicago.
Widely regarded as the central figure in the development of the new classical approach to macroeconomics, he received the Nobel Prize in Economics in 1995. He has been characterized by N. Gregory Mankiw as “the most influential macroeconomist of the last quarter of the 20th century.”
Lucas is well known for his investigations into the implications of the assumption of the rational expectations theory. Lucas (1972) incorporates the idea of rational expectations into a dynamic general equilibrium model. The agents in Lucas’s model are rational: based on the available information, they form expectations about future prices and quantities, and based on these expectations they act to maximize their expected lifetime utility. He also provided sound theory fundamental to Milton Friedman and Edmund Phelps’s view of the long-run neutrality of money, and provide an explanation of the correlation between output and inflation, depicted by the Phillips curve.
Lucas (1976) challenged the foundations of macroeconomic theory (previously dominated by the Keynesian economics approach), arguing that a macroeconomic model should be built as an aggregated version of microeconomic models while noting that aggregation in the theoretical sense may not be possible within a given model. He developed the “Lucas critique” of economic policymaking, which holds that relationships that appear to hold in the economy, such as an apparent relationship between inflation and unemployment, could change in response to changes in economic policy. That led to the development of new classical macroeconomics and the drive towards microeconomic foundations for macroeconomic theory.
Lucas developed a theory of supply that suggests people can be tricked by unsystematic monetary policy; the Uzawa–Lucas model (with Hirofumi Uzawa) of human capital accumulation; and the “Lucas paradox”, which considers why more capital does not flow from developed countries to developing countries. Lucas (1988) is a seminal contribution in the economic development and growth literature. Lucas and Paul Romer heralded the birth of endogenous growth theory and the resurgence of research on economic growth in the late 1980s and the 1990s.
He also contributed foundational contributions to behavioral economics, and provided the intellectual foundation for the understanding of deviations from the law of one price based on the irrationality of investors.