A dataset on radical and extremist attitudes in Europe.

This dataset introduces the first cross-nationally validated measurement scales for left-wing and right-wing radicalism, and general political extremism, along with an implicit association test (IAT) for implicit political extremism in the Western world. It includes data from more than 18,000 participants collected through ten surveys conducted between 2022 and 2024 in France, Germany, Great Britain, Greece, Hungary, the Netherlands, and the United States. The dataset facilitates comparative analyses of the origins and consequences of radical and extremist attitudes across different political systems. Moreover, by linking attitudinal measures with behavioral indicators such as party support, it provides a foundation for examining how latent forms of extremism are translated into political action. Beyond extremism research, the dataset contributes to the broader study of democratic resilience, political polarization, and ideological belief structures.