Public opinion during a presidential campaign: Distinguishing the effects of environmental evolution and attitude change

This paper develops a spatial model which distinguishes between different sources of temporal variability in public opinion over the course of an election campaign. Candidates and citizens are shown as points within a space. The candidate points are fixed, but their relative positions can change as a result of change over time in the dimension weights. If this occurs, it represents environmental evolution. The individual citizens' points also can move within the space, independently of the external environment. To the extent this occurs, it represents attitude change. The model is tested with data from the CPS 1980 National Election Study. The empirical results show that much of the variability in public evaluations of the candidates is due to evolutionary changes in the electoral environment, rather than individual-level attitude changes. Furthermore, that attitudinal change which does occur is strongly delimited by factors like partisan strength, interest in the campaign, and political participation. (C) 2009 Elsevier Ltd. All rights reserved.