Much time was wasted and ink spilled in the late 1960s and early 1970s trying to interpret the lagged effect of prices on wages as reflecting adaptiv… - Robert J. Gordon

Part of the downfall came early and on theoretical grounds, with the realization that real-world information lags for aggregate variables like the price level and money supply were much too short to rationalize the persistent multiyear deviations from equilibrium that seemed to characterize business cycles in most industrialized countries. The second dubious assumption, continuous market clearing, was viewed more critically once it was recognized that it was not an inextricable concomitant of rational expectations, especially when Stanley Fischer (1977) and Edmund Phelps and John Taylor (1977) showed that rational expectations could be embedded in a model containing real-world institutional features like multiperiod wage and price contracts to generate nonmarket-clearing behavior. Once Fischer and Phelps-Taylor had shown that rational expectations by itself was a necessary but not a sufficient condition to validate new-classical policy conclusions, the race was on to develop the new-Keynesian theory based on rational expectations and one or another institutional impediment to continuous market clearing.

New-classical economics has been undeniably influential, but not in the way that its three prominent creators originally imagined. Its most important contribution to macroeconomics, the assumption of rational expectations, was stolen almost immediately, and applied more fruitfully, by the new Keynesians.

The postwar era has not surprised Arthur Burns, for business cycles have continued their "unceasing round." although the United States recession of 1981-82 was the eighth since World War II and the deepest postwar slump by almost any measure, the 1983-84 recovery displayed an upward momentum sufficient to befuddle forecasters and delight incumbent politicians. Nor would a reincarnated Joseph Schumpeter be disappointed in the current status of business cycle research in the economics profession. To be sure, interest in business cycles decayed during the prosperity of the 1960s, as symbolized in the 1969 conference volume, Is the Business Cycle Obsolete? and in Paul Samuelson's remark the same year that the National Bureau of Economic Research "has worked itself out of one of its first jobs, namely, the business cycle."