STATS ARTICLES 2006
Healthiest or Least Healthy State?
Rebecca Goldin, Ph.D, December 7, 2006
A study in demographics can yield surprising results.
Minnesota has been ranked the “healthiest state” in the United States by the United Health Foundation, a nonprofit healthcare watch group. And Louisiana fell from 49th place last year to the 50th in 2006 (replacing Mississippi for the spot).
But the titles of Best and Worse could be misleading, for a variety of simple statistical principles.
Consider, for example, that in the United States blacks routinely have worse health than whites. According to the Centers for Disease Control, “For many health conditions, non-Hispanic blacks bear a disproportionate burden of disease, injury, death, and disability.” This very fact has prompted a flurry of media coverage over the past year. While the causes of the disparity are debatable, it remains a persistent truth. Similarly, poor people get worse coverage than the rich.
Now consider that the percentage of black Americans living in Louisiana is 33 percent, according to the Louisiana 2000 census, compared to four percent of the population in Minnesota, according to their 2000 census. Similarly, the percentage of those living under the poverty line in Louisiana is much higher than those under the poverty line in Minnesota.
These facts can lead to strange seemingly contradictory mathematical conundrums. Consider the particular statistic of infant mortality. Minnesota might have a higher rate of infant death both among blacks and also among whites, and still have an overall lower infant death rate.
Louisiana is about 33 percent black, 64 percent white, and the rest of the population is either another race, or of mixed racial background. In contrast, Minnesota is approximately four percent black and 90 percent white, and the rest other racial identity or of mixed race. Suppose that the two states do equally well on infant mortality for those people neither black nor white, but that Louisiana has better statistics for both blacks and for whites.
Hypothetically, assume that the infant mortality rate for blacks in Louisiana is 12 deaths per 10,000 live births, and for whites is 4 deaths per 10,000 live births. In contrast, suppose that in Minnesota there were 15 deaths per 10,000 live births among blacks, and 5 deaths per 10,000 live births among whites. Note that Minnesota does worse for both groups than Louisiana does. Even worse: in these invented numbers, Minnesota does worse in managing the discrepancy between blacks and whites than Louisiana does.
But when the numbers are crunched, a funny thing happens. For every 10,000 live births, Louisiana experiences about 6.7 deaths, while Minnesota experiences only 5.4 deaths. Minnesota wins in the race to keep infant mortality down, even though it did worse both for whites and for blacks.
The same kind of calculation can be done for those who are poor versus those who are above the poverty line, or for those with health insurance versus those without. Any time there are big disparities in the demographics of the population, comparisons can be tricky.
Is it right to split groups up into demographics and measure which state is healthiest that way? Or does it make more sense to lump everyone together?
It depends what you want to measure, of course. If your interest is to know what your own health care would be if you moved to a particular state, you ought to look for a health assessment of those people in your own demographic category. If your interest is to know which state needs the most assistance in decreasing infant mortality and money cannot be allotted using demographics, then bunching people together for an overall assessment makes sense.
What sorts of measurements might get at health disparities that are not demographically based? How about infant mortality rates among women getting appropriate prenatal care? What about the rate of death due to hospital error? What about simply applying standard statistical techniques to offset the demographic differences?
But fault the Louisianans for a poor showing on health care? It seems a little unfair, unless the discrepancies between the states hold even after controlling for factors such as race, income, etc. If they do, Louisiana is lagging behind Minnesota. If they don’t, the state is simply dealing with a population that is harder to keep healthy, having nothing to do with the state itself – and everything to do with where people live.