Gebhardt, MarkusDeVries, Jeffrey Matthew2020-04-012020-04-012019http://hdl.handle.net/2003/39079http://dx.doi.org/10.17877/DE290R-20998This dissertation examines the Strengths and Difficulties Questionnaire (SDQ) in German classrooms. In doing so, the factor structure of the SDQ was found sufficiently similar to established 5- and 3- factor models. In the three included articles, longitudinal changes in SDQ performance are examined, and the SDQ is connected to student performance (i.e., grades and competency) and the Perception of Inclusion Questionnaire (PIQ). This establishes not only a validation of the structure of the SDQ, but also external comparisons. Through development in the primary school level, problem scores on the SDQ were increased, while prosocial behavior decreased. This was in keeping with the bidirectional feedback model, indicating that such problems affect academic performance, which can then spawn additional problems, creating a feedback loop. Next, high social problems scores on the SDQ were linked to worse performance in math and German in secondary schools, thus establishing a connection between problems and academic achievement. Finally, a possible mechanism of this process was examined via the comparison to the PIQ, which demonstrated that children with internalizing and externalizing problems in inclusive classrooms feel less included and also self-report a lower level of academic self-concept.enInclusionStrengths and difficulties questionnaireInvariance370TextSDQSchuleInklusion