Statistics 101

In today's Democratic debate at Dartmouth College, Tim Russert proved he doesn't understand statistics. He said, as part of a question on Social Security:

"The reason Franklin Roosevelt set the age of eligibility to 65 — that was life expectancy. You made it onto the program for a month or two, and that was it."

Life expectancy figures simply don't work that way. An average life expectancy of 65 does not mean that adults are likely to die at age 65. Historically speaking, many children died at birth, or shortly after. All those 0s and 1s weighted the average lower. In fact, in 1930 the average life expectancy was only 59.2 years. But if you had already made it to age 65, on average you could expect to live an additional 12.2 years, not "a month or two" as Tim stated.