ECOLOGICAL REGRESSION AND VOTING-RIGHTS

Ecological regression is a statistical mainstay in litigation brought under the Voting Rights Act of 1965. The technique is discussed in the context of a suit against the County of Los Angeles that came to trial in 1990. Ecological regression depends on very strong assumptions about political behavior. The authors identify these assumptions and show that they are not supported by the data. Also described is an alternative "neighborhood model," which is a priori more plausible and fits the facts better. The neighborhood model leads to quite different conclusions about voting behavior.