"Wealthier is healthier." This characteristically pithy observation by Lant Pritchett and Lawrence H. Summers (1993) summarizes one of the most firmly-established findings about population health. Health is closely related to social class. This "health gradient" shows up in all the developed democracies. On a wide variety of measures, people of higher socioeconomic status tend to be healthier than those on the lower rungs of the socioeconomic ladder.