For decades, experts have puzzled over why the US spends more on health care but suffers poorer outcomes than other industrialized nations. Now Elizabeth H. Bradley and Lauren A. Taylor marshal extensive research, including a comparative study of health care data from thirty countries, and get to the root of this paradox: We've left out of our tally the most impactful expenditures countries make to improve the health of their populations--investments in social services.

In The American Health Care...