Analyzing Cognitive Demands of a Scientific Reasoning Test Using the Linear Logistic Test Model (LLTM)

The development and evaluation of valid assessments of scientific reasoning are an integral part of research in science education. In the present study, we used the linear logistic test model (LLTM) to analyze how item features related to text complexity and the presence of visual representations influence the overall item difficulty of an established, multiple-choice, scientific reasoning competencies assessment instrument. This study used data from n = 243 pre-service science teachers from Australia, Canada, and the UK. The findings revealed that text complexity and the presence of visual representations increased item difficulty and, in total, contributed to 32% of the variance in item difficulty. These findings suggest that the multiple-choice items contain the following cognitive demands: encoding, processing, and combining of textually presented information from different parts of the items and encoding, processing, and combining information that is presented in both the text and images. The present study adds to our knowledge of which cognitive demands are imposed upon by multiple-choice assessment instruments and whether these demands are relevant for the construct under investigation—in this case, scientific reasoning competencies. The findings are discussed and related to the relevant science education literature