A while ago, I criticized a new paper on the supremacy of the U.S. healthcare system that was being touted by Gary Becker and Greg Mankiw. The paper, by Samuel Preston and Jessica Ho at the University of Pennsylvania, showed that mortality trends for prostate and breast cancer were much better in the U.S. than in other advanced countries. My main beef was that Preston and Ho's research design was too blunt to really pick up on why this was the case. But I see that an updated NBER version of the paper has more details on what could be behind the better U.S. outcomes.

On prostate cancer:

Declines in prostate cancer mortality have been attributed to both PSA screening and improvements in treatment ... An individual-level population model that used counterfactuals to simulate US mortality and incidence of advanced-stage prostate cancer concluded that two-thirds of the decline in mortality between 1990 and 1999, and 80% of the decline in distant-stage incidence, was attributable to expanded PSA testing (Etzioni et al. 2008).

On breast cancer:

A careful, detailed simulation for the US by Berry et al. (2006) concluded that “We can say with high probability that both screening and adjuvant therapy have contributed to the reductions in U.S. breast cancer mortality observed from 1975 (and especially from 1990) to 2000. Our best estimate is that about two-thirds of the reduction is due to therapy and one-third to screening” (Berry et al. 2006:36). Using less precise methods, Blanks et al. (2000) reached a similar conclusion about the decline in breast cancer mortality in England and Wales from 1990 to 1998.

The problem here is that a recent NYT story (hat tip: Karl Smith) points to stronger evidence against the benefits of screening:

The American Cancer Society, which has long been a staunch defender of most cancer screening, is now saying that the benefits of detecting many cancers, especially breast and prostate, have been overstated.

It is quietly working on a message, to put on its Web site early next year, to emphasize that screening for breast and prostate cancer and certain other cancers can come with a real risk of overtreating many small cancers while missing cancers that are deadly.

Which says to me that a large part of what Preston and Ho are picking up in their results are unexplained correlations that may have nothing to do with the benefits of America's healthcare system. Now, I think there is much truth to the contention that US healthcare is a growing part of the GDP pie as a result -- not in spite -- of economic progress. So improved technology could definitely explain some of the improvements in US mortality from prostate and breast cancers. That said, it doesn't mean the system couldn't use improvement -- not by a long shot.