Research and Analysis by Selig D. Lesnoy
Social Security and Private Saving: A Reexamination of the Time Series Evidence Using Alternative Social Security Wealth Variables
In an important article in the Journal of Political Economy , Martin Feldstein estimated that the introduction of the social security system had reduced personal saving by 50 percent, with serious consequences for capital formation and output. His conclusion was based on a consumer expenditure function estimated with U.S. time series data and incorporating a social security wealth variable of his construction.
The original intent of this paper was to examine the sensitivity of Feldstein's conclusions to certain assumptions underlying his construction of the social security variable. In particular, we wanted to examine the implication of his assumptions concerning how individuals perceive future benefits and taxes.
In a recent article in the Journal of Political Economy (Leimer and Lesnoy 1982), we presented new time series evidence that cast considerable doubt on earlier evidence presented by Martin Feldstein (1974) which implied that social security had a large and statistically significant negative effect on personal saving in the United States. Our results may be summarized as follows: First, the social security wealth variable used by Feldstein was seriously flawed as a result of a computer-programming error. Simply correcting this error substantially changes the estimated effect of social security on saving. Second, the statistical evidence depends upon assumptions which are embedded in the construction of the social security wealth variable. These assumptions relate, first, to how individuals form their expectations about the social security benefits they expect to receive and the social security taxes they expect to pay and, second, to estimates of the number of workers, dependent wives, and surviving widows who will receive benefits. Adopting reasonable assumptions that differ from those used by Feldstein leads to generally weaker estimates of the relationship between social security and saving. Finally, the estimated relationship between social security and saving is acutely sensitive to the period of estimation examined. We concluded that the time series evidence simply does not support the hypothesis that social security has substantially reduced personal saving in the United States.
The purpose of this paper is to consider several alternative specifications of the consumer expenditure function.