This poster evaluates the comparability of the GGS-II across 12 countries, emphasizing the consistency of responses to the core questionnaire. High comparability scores were observed in Austria and Denmark (99%), while Sweden and Germany showed lower scores (41% and 85%, respectively). The methodology involves calculating the comparability rate based on the alignment of country-specific questionnaires with the core GGS-II Baseline Questionnaire, excluding optional and country-specific questions. The results underscore the importance of harmonizing survey instruments to enhance data quality and facilitate cross-national research.