American Indians without Tribes in the 21st Century.

Among American Indians and Alaska Natives, most aspects of ethnicity are tightly associated with the person's tribal origins. Language, history, foods, land, and traditions differ among the hundreds of tribes indigenous to the United States. With this in mind, we ask why almost one million American Indians failed to respond to the tribal affiliation part of the Census 2000 race question. We investigate four hypotheses about why one-third of multiracial American Indians and one-sixth of single-race American Indians did not write any response to the tribal affiliation question: (1) survey item non-response which undermines all fill-in-the-blank questions, (2) a non-salient tribal identity, (3) a genealogy-based affiliation, and (4) a mestizo identity which does not require a tribe. We use multivariate logistic regression models and high-density restricted-use Census 2000 data. We find support for the first two hypotheses and note that predictors differ substantially for single-race versus multiple-race American Indians.