Berry, William, Evan Ringquist, Richard Fording and Russell Hanson. “The Measurement and Stability of State Citizen Ideology.” State Politics and Policy Quarterly, 7 (Summer 2007): 111-32 & “A Rejoinder: The Measurement and Stability of State Citizen Ideology”: 160-66.

Does state political ideology change over time? Brace et al. (2004, 537) say no, based on their analysis of three longitudinal measures of state citizen ideology: Berry et al.’s (1998) indicator that relies on election results and congressional roll call votes; and two indicators Brace et al. construct from ideological self-placement items, one using GSS and ANES survey results, the other employing surveys conducted by CBS/New York Times. The authors imply that the ideological stability they detect precludes the possibility that state citizen ideology influences state policy. This implication, however, stems from Brace et al.’s definition of meaningful ideological change as differences in the relative ideological positions of states over time, rather than absolute changes in ideology within states. We contend that their assertion that relative ideological stability guarantees that ideology has no impact on policy is mistaken. Moreover, we maintain that the evidence they provide that state ideology is relatively stable is flawed. Brace et al. maintain that their CBS/New York Times and GSS/ANES indicators are valid measures of state citizen ideology, but that the Berry et al. indicator is not. We note the importance of distinguishing between self-identification (or symbolic ideology) and policy mood (or operational ideology). We find that the Berry et al. measure is valid as an indicator of policy mood, but invalid as a measure of self-identification. In contrast, the CBS/New York Times and GSS/ANES measures are invalid as indicators of policy mood. They are valid indicators of self-identified ideology, but they prove to be highly unreliable. Although a measure of self-identified ideology is useful for answering some questions, we argue that an indicator of policy mood is more appropriate when studying the impact of public opinion on public policy, and reiterate our confidence in using the Berry et al. measure for that purpose.