Item and rater variabilities in students' evaluation of teaching in a university in Ghana: application of Many-Facet Rasch Model

This research examined the item and rater variabilities in students' evaluation of teaching and courses exercise at the University of Cape Coast (UCC) through the lenses of the Many-Facet Rasch Model (MFRM). The study covered students during the 2019/2020 academic year in the selected university, analysing secondary data obtained from the Directorate of Academic Planning and Quality Assurance, UCC (DAPQA-UCC). The data were analysed by conducting partial credit MFRM analyses. It was found that the sources of measurement errors in the student evaluation exercise included halo effect, non-functional item structure, inconsistent students' ratings, rater leniency, and non-functional rating scale. It was concluded that data from students' appraisal of lecturers' teaching should be used with caution. It was recommended that DAPQA-UCC and the university management should train students on the evaluation of teaching, as well as review the existing evaluation form for appraising courses and teaching by subjecting the instrument to rigorous validation procedures.