One of the most prominent economic theorists of the twentieth century, Arrow has made contributions to a wide range of areas, from rational expectations to collective choice; from the allocation of risk to the economics of uncertainty; from technological innovation to production and growth. He has also extended the domain of economic analysis to issues such as information, health and safety regulation, education, the environment, racial discrimination and arms control.
While highly varied, his work is nevertheless characterized by a deeply-rooted libertarianism and close attention to ethical issues. Hence his rejection of ideology, his emphasis on the need to link the efficiency of markets with distributive justice and the importance of individual and collective responsibility.