Some further aspects of ecological regression analysis

Ecological regression analysis is concerned with the inference of individual level relationships from aggregate level data. A first method for this type of inference, which here is compared to Leo Goodman's (1953) method, was presented by the German statistician F. Bernstein (1932). His hypothetical example, voting behaviour depending on age, is reanalysed, using historical data from the Reichstag elections, with special emphasis on the NSDAP vote. Furthermore it is demonstrated, why age is a bad predictor is ecological regression analysis, and how unreliable predictors can be diagnosed by means of several simple coefficients.