However, in the case of Feldstein's social security findings, it is not clear that a consensus yet exists.

Says Professor of Economics Lawrence H. Summers, once a student of Feldstein, "I don't think the evidence either way [on the effects of social security on private savings] is absolutely conclusive."

But, says Feldstein, "There is controversy about any theory or empirical study that has policy significance...The closer you get to the frontier on any specific subject, the more likely you are to get controversy."

Social Security Report

Feldstein, who returned to Harvard last year after serving as the chairman of President Reagan's Council of Economic Advisors, has been criticized outside the University as well since he first published his social security findings in 1974.

Feldstein's conclusions had wide-ranging implications for national policy at a time when economists and public officials were worried about a major recession and widely perceived a need to restructure the aging social security system which was faced with serious financing problems.

Feldstein's paper prompted studies by several economists. While some of this work supported his conclusions, some did not, and none found as large an effect on private saving as Feldstein did, according to economist Henry J. Aaron of the Brookings Institute, a liberal Washington-based think-tank.

Most recently, in a January report by the Social Security Administration, economists Selig D. Lesnoy and Dean R. Leimer challenged Feldstein's choice of statistical model, his data, and the conclusions he draws from those data.

Feldstein says that Leimer and Lesnoy's criticisms of his data and model do not detract from his conclusions because his model works even without the contested data.

Feldstein insists, however, that he is not alone in his view. "The fact that a lot of different studies have come to similar conclusions from quite different kinds of data makes them all more convincing," he says.

Feldstein says he has statistical backing for his position based on several econometric studies he has made since 1974. The studies in dispute use computer analyses of historical data on private saving to make predictions about the effect of anticipated social security benefits on savings from the "life-cycle" model.

But, says Brookings economist Aaron, "The jury is definitely out on how social security effects saving."

The life-cycle model assumes that individuals make a financial plan for their whole lives based on their estimated present and future wealth and that they save according to this plan and consume all their savings during their lifetimes. Studies by several economists have generated erratic results using the model. According to Aaron, these studies "indicate that the life-cycle model does not correctly describe the behavior of many or most savers."

Lesnoy and Leimer challenge both the statistical soundness of Feldstein's computer analysis and his choice of evidence, and a number of economists seem to share their concern.

Says MIT Professor of Economics Edwin Kuh, "When you have a reasonable theory and strong data it is practical to test hypotheses with time series analysis [the type of computer study Feldstein used], but in the case of the Feldstein controversy these conditions were not met."