Ideological Constraint Analysis

Constraint is the functional interdependence of political attitudes, the degree to which holding one position implies holding related positions, typically because an overarching belief or ideology ties them together. High constraint means attitudes are bundled and predictable; low constraint means they vary independently. Converse argued that elites display high constraint while much of the mass public does not, raising questions about citizen ideological competence.

Random measurement error in survey items attenuates observed correlations toward zero, so a public whose true attitudes are constrained can appear unstructured simply because the questions are noisy. This was a central critique of Converse: some apparent lack of constraint reflected unreliable single-item measures rather than incoherent beliefs. Latent-variable models that separate true score from error help correct this attenuation.

Constraint is attitudes cohering around an ideological principle; sorting is attitudes aligning with party identity. The public can grow more correlated in its issue positions because people adopt their party's positions (sorting) rather than because they reason from ideology (constraint). Baldassarri and Gelman showed that much of the apparent rise in coherence is partisan sorting, which has different implications for polarization.