School of economic thought based on the work of 19th-century economists such as Alfred Marshall, using marginal theory to modify classical economic theories, and placing greater emphasis on mathematical techniques and theories of the firm. Neoclassicists believed competition to be the regulator of economic activity that would establish equilibrium between demand and supply through the operation of market forces.
Neoclassical economics was criticized by the English economist John Maynard Keynes for its analysis of output and employment in the whole economy. The US economist Milton Friedman reasserted neoclassical principles of macroeconomics.