Teachers' Judgments of Students' School-Wellbeing, Social Inclusion, and Academic Self-Concept: A Multi-Trait-Multimethod Analysis Using the Perception of Inclusion Questionnaire.

Students' school well-being, social inclusion, and academic self-concept are considered important outcome variables of schools. In the present study, these three variables were examined from teachers' and students' perspective (grades 5-9). The aim of the study was to investigate the construct validity (convergent and discriminant validity) of the teacher's version of the Perception of Inclusion Questionnaire (PIQ). Further, we investigated whether or not it is meaningful to include the perspective of a second teacher. The dataset consists of PIQ ratings of 151 students as well as ratings from two main subject teachers. The results for psychometric properties show that the students' as well as the teachers' version of the PIQ is suitable for secondary school students. The confirmatory factor analyses demonstrated good model fit for the three-dimensional factorial structure. By excluding one teacher's rating from the model, the multitrait-multimethod analysis provided indicators for the PIQ's construct validity (convergent and discriminant validity) of the traits and discriminant validity of the methods.