An unsuccessful replication of “Social Security, Induced Retirement, and Aggregate Capital Accumulation” by Martin Feldstein

In the last video, we mentioned a famous study by Marty Feldstein that claimed that the Social Security program in the United States led to reduced long-term savings in American households. This paper may have influenced policy directly as Dr. Feldstein was an advisor to former President Ronald Reagan.

Eight years later, however, (during the Reagan presidency) Dean Leimer and Selig Lesnoy of the U.S. Social Security Administration attempted to replicate the famous study and uncovered a programming error, as well as what they deemed unreasonable assumptions involved in how the social security wealth variable was constructed. Once these errors and assumptions were corrected, Leimer and Lesnoy found a much weaker relationship between social security and personal savings. In fact, their results suggest that social security may have contributed to increased savings.

This is just one example of how a pure replication led to vastly different conclusions than the original paper. The policy implications were also far-reaching.

It is also an example of a graceful and honest acknowledgment of the error by the original article’s author, Dr. Feldstein, who later stated in his reply to the replication:

“I am embarrassed by the programming error that Dean Leimer and Selig Lesnoy uncovered but grateful to them for the care with which they repeated my original study (Feldstein 1974). They set an admirable example of the tradition of replication on which all scientific work ultimately rests. As economic research increasingly involves large and complex computer programs to analyze microeconomic data sets or to simulate models that cannot be solved analytically, replication studies like that of Leimer and Lesnoy (“Social Security and Private Savings: New Time- Series Evidence,”…) should become increasingly important.”

You can read the entirety of each paper by clicking on the links in the SEE ALSO section at the bottom of this page. The reply by Martin Feldstein has limited access, but you should be able to get a good idea of his response from the first page or quote we included above.

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Optional Recess: Stereothreat!

If you have a spare 40 minutes, I recommend listening to an episode of the science podcast Radiolab called “Stereothreat”, which discusses a famous study that is now the subject of an adversarial replication.

The study claimed to show that a simple change in how test questions are presented can alter how well students perform on the test. Specifically, telling test-takers that women or people of color do well on a test leads to performance improvements of those identified populations.

These findings have recently been called into question. And now multiple teams of researchers, including an author of the original study, are now working to see if they can replicate the study. Stay tuned!

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Reference

Feldstein, Martin. 1974. “Social Security, Induced Retirement, and Aggregate Capital Accumulation.” Journal of Political Economy 82 (5): 905–26.

Feldstein, Martin. 1982. “Social Security and Private Saving: Reply.” Journal of Political Economy 90, (3):630-642.

Leimer, Dean R., and Selig D. Lesnoy. 1982. “Social Security and Private Saving: New Time-Series Evidence.” Journal of Political Economy 90 (3): 606–29.