Changes in Social Security rules between 1992 and 2004 led to more men aged 65 to 67 staying in full-time work and increasing their labor force participation. These changes encouraged delaying retirement, returning to work after retiring, and partial retirement. The increase in labor force participation for married men ages 65 to 67 from 1998 to 2004 was partly due to Social Security changes. However, the decrease in labor force participation for married men in their fifties during this period was not related to Social Security changes, but possibly due to other factors like disability.