NBER Working Paper #2982 May 1989 NEW CLASSICALS AND KEYNESIANS, OR THE GOOD GUYS AND THE BAD GUYS Old-style Keynesian models relied on sticky prices or wages to explain unemployment and to argue for demand-side macroeconomic policies. This approach relied increasingly on a Phillips-curve view of the world, and therefore lost considerable prestige with the events of the 1970s. The new classical macroeconomics began at about that time, and focused initially on the apparent real effects of monetary disturbances. Despite initial successes, this analysis ultimately was unsatisfactory as an explanation for an important role of money in business fluctuations. Nevertheless, the approach achieved important methodological advances, such as rational expectations and new methods of policy evaluation. Subsequent research by new classicals has deemphasized monetary shocks, and focused instead on real usiness cycle models and theories of endogenous economic growth. These eas appear promising at this time. another development is the so-called new Keynesian economics, which includes long-term contracts, menu costs, efficiency wages and insider-outsider theories, and macroeconomic models with imperfect competition. Although some of these ideas may prove helpful as elements in real business cycle models, my main conclusion is that the new Keynesian economics has not been successful in rehabilitating the Keynesian pproach Robert J. Barro Harvard University Department of Economics Littauer Center Cambridge, MA 02138