Using polytomous IRT models to evaluate theoretical levels of understanding models and modeling in biology education

Abstract

Forced choice-tasks have been developed to assess students’ (N = 901) understanding of models and modeling in biology based on a theoretical structure differentiating five aspects and three levels of understanding (Upmeier zu Belzen & Krüger, 2010). The data have been analyzed by using the partial credit and the rating scale model to evaluate the assumption of an increasing degree of difficulty from level I to level III in each aspect. The findings suggest (1) that the levels of understanding are not equidistant across all aspects and (2) that the theoretically developed levels of understanding are in fact ordered by difficulty. However the latter issue needs further investigations since the present findings are not clear for all five aspects of the theoretical structure.