Using Rasch modeling to compare scientific conceptions of high-school and university students

Enhancing student learning outcomes for university science students requires careful consideration of the conceptions and prior experiences brought to the learning situation. Too often lecturers of science assume a degree of understanding that is not evident and this ultimately impacts on student cognitive engagement, enthusiasm and retention. This paper compares and contrasts the conceptions of diffusion and osmosis held by different groups of science students by using the Partial Credit Rasch Model. All 240 students completed five extended-response questions that were coded using a cognitive structural model to produce ordinal level data. Results from the Rasch analysis indicate that students use similar cognitive processes with conceptual understanding being independent to the level of education.