Ideology Strength Versus Party Identity Strength: Ideology Strength Is the Key Predictor of Attitude Stability

We investigate the relationship between attitude instability and both party identity strength and ideology strength. We test the explorative hypotheses that higher party identity strength (H1) and ideology strength (H2) predict more attitude stability using intensive longitudinal data collected in the United States every 2 weeks over 1 year (Study 1, N = 552) and in the Netherlands over 6 months (Study 2, N = 1,670). We found mixed support for H1: In the United States, there was no association between party identity strength and attitude stability. In the Netherlands, people with stronger party identity had more stable attitudes. We found stronger support for H2: Individuals with a stronger ideology than average had more stable attitudes in the United States and the Netherlands. The context-dependent nature of relations is discussed.