tions of Indian Health Service (IHS) enrolled patients were incorrectly classified as non-American Indian (Korenbrot et al., 2003; see also Grossman, 2003).
A third complication involves the way the major groups are defined. Though they reflect major social distinctions, they may or may not reflect the distinctions that are most relevant in assessing health. It is difficult to tell a priori what racial and ethnic distinctions would be most productive for health research, and some possible distinctions may involve groups too small to be studied nationally. It is important to keep in mind, however, that each of these five major groups we consider is in fact an amalgam of many smaller groups that, in a previous era, might have been separately distinguished, and that may still consider themselves distinct.
Finally, note that the relationship between group membership and health is somewhat different with regard to American Indians and Alaska Natives because of the existence of the IHS. Tribes employ very explicit eligibility criteria to define membership, which are formally ratified by the Bureau of Indian Affairs, U.S. Department of the Interior. These criteria vary among tribes, as it is within their purview to define membership, ranging from different degrees of blood quantum to other, nonconsanguineal forms of descent reckoning. Tribal enrollment, in turn, determines eligibility for access to federally sponsored health care provided through the IHS. There is a strong, but not isomorphic, relationship between tribal enrollment and residence: most American Indians/Alaska Natives living on or near reservations are enrolled tribal members, but as much as 60 percent of the enrolled population lives off-reservation, in rural, suburban, and urban areas. Relatively few individuals who self-identify as American Indian and Alaska Native but are nonenrolled in tribal registers reside in reservations. Thus, in this subpopulation, the issue of identification is not simply a psychological phenomenon but one that has enormous implications for access to health care.
The health differences in late life among the five major groups—Hispanics, whites, blacks, Asians, and American Indians and Alaska Natives—are complex but can be briefly summarized. Blacks generally have worse health than other groups. American Indians and Alaska Natives, especially those on reservations, are also less healthy than other groups except blacks. Whites are usually taken as the standard against which other groups are compared, but they are not necessarily in the best health. Hispanics appear to be healthier than whites on a number of measures, though not all. Asians are generally in better health than any other group (Hummer et al., 2004).
These generalizations are based on various indicators of health, espe-