Education is one of the most important predictors—usually, in fact, the most important predictor—of many forms of political and social engagement—from voting to chairing a local committee to hosting a dinner party to trusting others. Over the last half century (and more) educational levels in the United States have risen sharply. In 1960 only 41 percent of American adults had graduated from high school; in 1998 82 percent had. In 1960 only 8 percent of American adults had a college degree; in 1998 24 percent had. Yet levels of political and social participation have not risen pari passu with this dramatic increase in education, and by some accounts [Putnam, 1995a; 1995b; 2000] have even fallen. For at least two decades, political scientists have mused about this paradoxical “puzzle” [Brody, 1978]. Recently, however, Norman Nie, Jane Junn, and Kenneth Stehlik-Barry [1996, hereafter NJS-B] have offered an elegant and potentially powerful resolution to this paradox, beginning with a crucial distinction between the “relative” and “absolute” effects of education. If more people now have a college degree, they argue, perhaps the sociological signifi cance of the credential has been devalued. Social status is, for example, associated with education, but we would not assume that just because more Americans are educated than ever before, America has a greater volume of social status than ever before. To the extent that education is merely about sorting people, not about adding to their skills and knowledge and civic values, then no puzzle remains to be explained. In fact, NJS-B conclude, participation is affected primarily by relative educational levels, and thus has not been (and should not have been expected to be) rising with aggregate educational levels. The distinction that NJS-B have introduced is important. Education has external effects, as well as internal ones. In principle, my behavior can be affected not only by my education, but also by that of others around me. The core issue is whether (holding constant my own education), I am more likely or less likely to participate politically and socially if those around me become more educated. Besides its academic inter