Political Legitimacy Building: Scale Development and Psychometric Evaluation in Two Peruvian Samples

Political legitimacy is a contested concept that poses measurement challenges, particularly in democratically fragile contexts like Peru. This study developed and validated the Attitudes Towards Political Legitimacy Building (APLB) scale, which assesses citizens' endorsement of democratic legitimacy principles. Data were collected from two Peruvian samples: a non-probability convenience sample –Lima, San Martín, and Loreto– (n = 279), and a stratified panel sample –Lima, Callao, Apurímac, Ayacucho, Cusco, and Puno– (n = 558). Exploratory factor analysis informed item refinement, whereas confirmatory factor analysis supported a six-item, two-factor structure: Common Good Orientation (CGO), reflecting concern for collective well-being, and Deliberative Consensus Orientation (DCO), emphasizing pluralistic debate and citizen participation. Both factors demonstrated adequate internal consistency and evidence of convergent and discriminant validity based on factor loadings, average variance extracted, and shared variance. Measurement invariance analyses supported strict invariance across sex and scalar invariance across electoral preferences in the 2021 Peruvian presidential election, but not across left-right political orientations. Both factors correlated negatively with Social Dominance Orientation and Perceived Legitimacy, providing evidence of theoretically expected relationships. Findings suggest that legitimacy based on democratic principles and the legitimation of a system are not the same thing, as the latter does not necessarily imply greater agreement with democratic principles. The APLB scale's brevity makes it suitable for non-WEIRD populations, though further validation across diverse populations is needed