The development of an instrument for measuring teachers' and students' beliefs about differentiated instruction and teaching in heterogeneous chemistry classrooms

Diversity and differences between students are the reality that teachers deal with daily. To address this reality, developments in education aim to provide teachers with the knowledge and requisite skills needed for differentiated instruction (DI). DI is a pedagogical-didactic approach that enables teachers to systematically address students' diverse learning needs. However, no validated instruments currently exist to measure or evaluate teachers' and students' beliefs toward DI in chemistry. Hence, there is a need to develop such questionnaires to examine students' and teachers' sense of self-efficacy (SE) and attitudes (AT). We describe the development and validation processes of such questionnaire that have been developed based on relevant literature on DI and on teachers' experience with DI in a heterogeneous classroom. The items were validated by experts' panel, a readability test, and a field test. A confirmatory factor analysis was undertaken to investigate the factor structure of the teachers and students' questionnaires based on pilot test reliability, Cronbach's alpha revisions, and rerun alpha. As a result, the SE and AT of students towards DI instrument entailed 38 items with a five-factor structure indicating a high reliability. Three factors of attitudes, (a) = 0.98, and two factors of self-efficacy, (a) = 0.91. The SE and AT of teachers entailed 55 items with a five-factor structure indicating a high reliability of self-efficacy, (a) = 0.95 and of attitudes towards DI in heterogeneous chemistry classrooms, (a) = 0.93.