“The good, the bad and the ugly…”
OK, here is what I know you’ve all been waiting for: the second installment of our course on demographics. Everything you need to know for the final exam can be found in an article published in the May 10, 2002, issue of Science: “The Broken Limits to Life Expectancy.”
First, the good news in the article: We are all going to be living longer than we thought, even taking into account that we expect to live longer. Consider this quote from the Science article: “Female life expectancy in the record-holding country has risen for 160 years at a steady pace of almost three months per year.” Longest life expectancy has gone from 45 years for women in Sweden in 1840 to about 85 years for women in Japan today, and it has increased linearly over the 160-year period (with a correlation coefficient of 0.992!). Even for men, the news is pretty good: Life expectancy for males is also growing linearly, though slightly more slowly. Guys, we’re living longer, but we’re falling behind. Before 1950, much of the gain in life expectancy resulted from reducing death rates among the younger age groups. Since then, improvements in survival of the over-65 cohort have driven life expectancy upward.
The bad news is that policy makers haven’t been very good at anticipating the expansion of life expectancy. I often preach against the dangers of extrapolation, which typically leads to overly optimistic future projections. In the case of life expectancy however, extrapolation has proven to be overly conservative. In 1928, a statistician named Louis Dublin used U.S. life tables to estimate what he thought was the lowest level to which the death rate could go for each age group and then used those numbers to predict the ultimate “hypothetical” life expectancy—a figure he calculated to be 64.75 years. One has to wonder how Dublin’s predictions influenced Social Security’s choosing 65 as the appropriate retirement age.
Adding to the confusion, of course, is the growing knowledge about replication in biological systems—since programmed cell death exists, it must have implications for the life expectancy of the organism as a whole. In other words, we think we know that there is a ceiling on ultimate life expectancy under the most optimal circumstances. But how high is that ceiling? No one can say for sure.
There is an ugliness to all this is as well: When we forecast future needs for Social Security, Medicare, nursing homes and so forth, even small increases in life expectancy can have a large effect on the number of elderly and thus the financial burden of social services. According to the Science article, “officials responsible for making projections have recalcitrantly assumed that life expectancy will increase slowly and not much further. They give politicians license to postpone painful adjustments to Social Security and medical care systems.”
Class dismissed. 
