The last chapter modeled technological progress as an increase in the number of types of products, N. In this chapter, we allow for improvements in t… - Robert Barro

In fact, the only person to rival Friedman for policy influence in the twentieth century is John Maynard Keynes, who had a strikingly different view of the role of government. Keynes was influential because he advocated more government intervention into what he perceived as poorly functioning private economies caught up in the Great Depression. In contrast to Keynes, Friedman put the main blame for the Depression on government failures, especially of monetary policy. Hence, the Depression did not make Friedman a fan of big government. He also found in the Federal Reserve’s failure to prevent deflation an argument in favor of monetary rules. As the world evolved— with low inflation becoming the major mission of central banks and free markets and secure property rights becoming the main policies to promote economic growth—Friedman surely won the intellectual battle.

If we look beyond the issue of monetary nonneutrality, then we do find areas of macroeconomics that use rational expectations and in which important recent progress has been made.

The role of expectations is not limited to monetary policy but is crucial in many areas of economics, as Bob showed in his later research on investment, unemployment, taxation, public debt management, and asset pricing. In all of these situations, the appropriate evaluation of policy takes account of the way that expectations would be rationally formed.