Medical Spending Variation: 1/2 Patients, 1/2 Places

In Miami, health care providers spent about $14,423 per Medicare patient in 2010. But in Minneapolis, average spending on Medicare enrollees that year was $7,819, just over half as much. In fact, the U.S. is filled with regional disparities in medical spending. Why is this?

One explanation focuses on providers: In some regions, they may be more likely to use expensive tests or procedures. Another account focuses on patients: If the underlying health or the care preferences of regional populations varies enough, that may cause differences in spending. In recent years, public discussion of this issue has largely highlighted providers, with the implication that reducing apparently excessive treatments could trim overall health care costs.

But now a unique study co-authored by MIT economists provides a new answer to the medical cost mystery: By scrutinizing millions of Medicare patients who have moved from one place to another, the researchers have found that patients and providers account for virtually equal shares of the differences in regional spending.

“We find it is about 50/50, half due to patients and half due to places,” says Heidi Williams, the Class of 1957 Career Development Associate Professor in MIT’s Department of Economics, and a co-author of a new paper detailing the study’s findings.

That’s MIT News ably summarizing the new Finkelstein, Gentzkow, and Williams paper, Sources of Geographic Variation in Health Care: Evidence From Patient Migration (ungated).

If the half of the variation that is due to place is inefficient (which could mean too low or too high but probably means too high given that the medical care curve is flat) then this puts an upper limit on the gains from standardization but still a quite high limit.

By the way, Finkelstein and Gentzkow are both recent John Bates Clark Medal awardees and Williams is a MacArthur “genius award” winner. Perhaps I should have titled this post, assortative co-authoring.