Deep Demographics: Understanding Local Variation in Donor Registration.

This is the first published study to examine in detail the demographic factors associated with willingness to register as an organ donor at a state motor vehicles bureau. It uses registration counts controlling for the size of the general population as the measure of willingness. Local variation in registration levels is modeled as a function of a set of local socioeconomic, racial/ethnic, and immigration characteristics; cluster analysis of social areas is used to probe the effects of nonlinear combinations of local social environment factors. Results show that residence in high minority areas, lower-income areas, and immigrant-heavy areas depresses registration levels but also that significant nonlinear combinations of factors are at work. Specifically, minority/immigrant areas tend strongly to have lower registration counts controlling for population regardless of socioeconomic status (SES), whereas registration in less prosperous areas depends largely on the racial, ethnic, and immigrant proportions in those areas. Moreover, the very highest SES neighborhoods in the study area (northern California minus greater Sacramento) have very high levels of donor registration despite high racial, ethnic, and national origin diversity.