It’s Not Race, It’s Public Transportation

Quite a bit of casual discussion over the last 2 months have focused on disparities in death rates between African-Americans and non-African-Americans.

It is important to emphasize what makes this discussion casual. Roughly, this comes from binning deaths by race, then dividing by the population of that race, and comparing the resulting rates. This is easy to do. But it is also fundamentally univariate, and thus subject to the most important form of bias in statistical work — omitted variables bias.

Pretty much no one should do analysis this way, and yet the media and politicians emphasize this sort of junk prominently.

There’s new research on this, where rates of death are regressed on a host of available data at the county level. I’ll quote from the conclusions:

The main findings as follows:

(i) For all four minorities, there is a strong positive correlation across counties between the minority’s population share and COVID-19 deaths. (ii) For Hispanic/Latino and Asian minorities those correlations are fragile, and largely disappear when we correct for education, occupation, and commuting patterns. (iii) By contrast, for African Americans and First Nations populations, the correlations are very robust. Regardless of what other factors are controlled for, a racial disparity in mortality rates persists. (iv) Surprisingly, for these two groups the racial disparity does not seem to be due to differences in income, poverty rates, education, occupational mix, or even access to healthcare insurance, which has been hypothesized by many observers to be a key source of the disparity. (v) A significant portion of the disparity can, however, be sourced to the use of public transit, which also explains a large fraction of the difference in mortality between Los Angeles and New York City.

Of course, while use of public transportation is generally associated with income within cities, it is not associated with income across cities. So this is not an absolute poverty result (which they did correct for), but rather a relative poverty result. In short, New York City was hit so heavily, particularly amongst minorities, because while it is on average a rich city, it is one in which the poor and minorities ride public transportation the most.

Do note that this is consistent with evidence reported in my February 26th post that evidence from Wuhan showed that shutting down public transportation we effective in containing the outbreak there. Once again, this tends to confirm poor choices made by political officials in New York City as leading to high death rates there. It is almost certain they would have had access to the same information that I did.

This also dovetails with a post I made last year about why infrastructure projects cost more in the U.S. than in other countries. That detailed a high degree of chauvinism amongst U.S. city politicians: if an idea does not come to them from within the U.S., they don’t listen.