Blood quantum and ethnic intermarriage in the Boas data set.

The data collected by Boas is biased toward employees of Indian agencies and school populations. The data show that intermarried Amerindians in the last century tended to marry back into the Amerindian population rather than into the general population, as in this century. Distributions of blood quantum within tribes show the intensity and duration of contact with the dominant society and other tribes. Amerindians who married into other tribes tended to choose spouses from contiguous tribes, but over one-fourth of spouses represented different language families. General hypotheses should be tested in the Boas data only with great caution and after correcting for historical factors if possible.