The article presents the development of a questionnaire to measure co-constructive cooperation in the context of inclusion in schools. The comprehensive model of coconstruction by Grosche, Fussangel, and Gräsel (2020a) represents the theoretical framework for the development of a larger number of items. The development of the questionnaire is pictured on the basis of four consecutive and independent sub-studies in which the number of items was continuously decreased, while the requirements for the measurement quality of the questionnaire were systematically increased. The final confirmatory factor analyses show that the questionnaire supports the theoretical dimensions of the co-construction model empirically in an adequate manner.

Keywords
Co-construction, questionnaire development, inclusion, cooperation