Suchergebnisse

Why do special interests defeat the people's will in American politics?

Are measures of legislator ideology derived from behavior accurate and valid? Past research says yes. However, the benchmarks used to reach these conclusions are often also based on legislators' public actions. Non-ideological factors that cause legislators to take specific issue positions may be highly related across measures and mistakenly lead scholars to believe that action-based estimates are valid. This question is important because scholars frequently wish to use action-based ideology estimates as explanatory variables. Without independent validation, it is unclear whether the results of these studies are valid or the product of measurement error. Applying an ideological benchmark that is not based on legislators' actions, I evaluate the validity of several commonly used ideology measures. The results show that action-based ideology measures produce valid estimates of legislator ideology.

Are measures of legislator ideology derived from behavior accurate & valid? Past research says yes. However, the benchmarks used to reach these conclusions are often also based on legislators' public actions. Non-ideological factors that cause legislators to take specific issue positions may be highly related across measures & mistakenly lead scholars to believe that action-based estimates are valid. This question is important because scholars frequently wish to use action-based ideology estimates as explanatory variables. Without independent validation, it is unclear whether the results of these studies are valid or the product of measurement error. Applying an ideological benchmark that is not based on legislators' actions, I evaluate the validity of several commonly used ideology measures. The results show that action-based ideology measures produce valid estimates of legislator ideology. 3 Tables, 1 Figure, 2 Appendixes, 74 References. Adapted from the source document.

Measures of political ideology are central to a broad range of political science scholarship. However, despite extensive evaluation of the relative characteristics of vote-based ideology measures, little scholarship examines their validity independent of legislator behavior. Ideological validity is overlooked because all existing measures are action based. To address this gap, this article applies an instrumental-variables technique called FILTER to assess the validity of two important measures of legislator ideology: NOMINATE and interest-group ratings. The technique is also applied to investigate whether the measured action-based ideology suffers from agenda bias. The results show that the measures produce valid estimates of legislator ideology. Moreover, FILTER offers an important alternative to existing action-based measures of ideology that might be inappropriate for use in some settings, such as when the dependent variable being studied is also action based.