Re-introduction to cross-cultural studies of the EPQ

Cross-cultural projects were undertaken, over some 25 years, to standardise the EPQ (both Adult and Junior forms) for many countries (See Appendix B for a list). Together with the rationale as to why these studies were undertaken, the statistical methodology is explained. Although the studies were published, it seemed timely to list them, together with their references, in this article. The authors also decided to publish the data for interested researchers and student psychologists, and it can be found in the Supplementary Material.