Beyond Common Spaces: Contrastive Scaling for Cross-Survey Structural Comparison

This paper develops contrastive scaling as a framework for cross-survey structural comparisons. Whereas conventional bridging estimates a latent space shared across surveys, contrastive scaling identifies dimensions along which the organization of responses differs across them. We illustrate its utility using the UTokyo-Asahi Survey and a joint U.S.-U.K. dataset. The results show that, over time, Japanese voters have become increasingly divided over issues related to the status of the Jieitai (Japan Self-Defense Force), particularly in the structure of response distributions. In cross-national comparisons, U.S. and U.K. voters differ primarily along country-specific issue dimensions—such as attitudes toward Trump and Brexit—rather than along a common ideological axis. These findings demonstrate that contrastive scaling provides a complementary perspective on survey comparison by identifying dimensions of differential variation, offering a new lens for studying how public opinion is structured across contexts.