This paper examines the economics of investing the central trust fund of Social Security in private securities. We note that switching from a policy of having the trust fund invest solely in special issue Treasury bonds to one where some of the portfolio holds common stocks amounts to an asset...

This paper examines the economics of investing the central trust fund of Social Security in private securities. We note that switching from a policy of having the trust fund invest solely in special issue Treasury bonds to one where some of the portfolio holds common stocks amounts to an asset...

Econometric analyses of treatment response commonly use instrumental variable (IV) assumptions to identify treatment effects. Yet the credibility of IV assumptions is often a matter of considerable disagreement, with much debate about whether some covariate is or is not a 'valid instrument' in...