by Pearl Hahn
Following my blog post about health care systems in France and Cuba compared with the United States, a wise reader, Joe Speroni, was compelled to write me an enlightening message concerning data for infant mortality rates and life expectancies.
Many (including columnist Paul Krugman) make the mistake of correlating nationalized health care systems with long life expectancies, pointing out that while the United States spends more on health care than others, our life expectancy and infant mortality rates are worse.
Mr. Speroni wrote, “there are many factors that weigh against a meaningful single number comparison of life expectancy. If populations being compared have the same characteristics, direct comparisons are more possible. If a population is stable (not growing or shrinking) and has been at the same birth rate for at least a generation, we would expect all ages be represented as an equal percent of the total, i.e. the distribution would be a graph represented as a straight line of percentage versus age. A difference in the average life expectancy of two populations might then be a measure of the quality of health care.
If a population is growing then we would expect the younger members to be a higher percentage of the population. Comparing two countries with exactly the same death rate for every age group- one growing and one stable- would give a lower average life expectancy for the one growing. It would appear to have a lower life expectancy even with exactly the same death rate by age.”
Here is the kicker in Mr. Speroni’s argument:
“The current population distribution by age is an important factor. The shape of the distribution curve is important. It won’t be a simple horizontal line for every population. Even in two populations with the same growth rate and the same expected death rate at a given age, if the percentage of members between 0 and 15 (years in age), 15-25, 25-40, 40-55, 55-70, and above 70, are different, we will compute different average life expectancies.
The U.S. has:
- the lowest median age, so one would expect that the percentages of younger members are higher than other countries.
- the highest birth rate so more infant mortality events
- the highest population growth rate, another factor that shows the distribution is skewed to the younger members and will be increasingly so in the future.
In the near future we should expect Germany and Japan to have an increasing life expectancy if all other factors remain the same. That may not be true if the quality of health care deteriorates as escalating costs require rationing.
The single comparison number of life expectancy is not a good measure of the quality of health care.”