Abstract

We examine the cross-national comparability of expert placements of political parties on the economic left–right dimension using a novel dataset combining data from Europe, Latin America, Australia, Israel, Canada, and the United States. Using anchoring vignettes and Bayesian Aldrich–McKelvey Scaling, we assess evidence of geographic and expert-level differential item functioning (DIF) in how experts interpret the left–right scale.

We find statistically significant but substantively small variations in how experts perceive party positions cross-nationally, particularly in terms of directional bias and the spread of their ideological placements. While the correlation between “raw” survey scores and DIF-corrected estimates is high (0.992), we observe meaningful deviations for individual parties, with larger discrepancies between rather than within regions.

These results indicate that the economic left–right dimension exhibits broad consistency in expert understanding across countries, yet researchers should still exercise caution when making cross-national comparisons, particularly across regions where expert perceptions show greater variation.