Faculty Scholarly Dissemination Grants


Measuring students conceptual understanding using pre and post assessments and the Rasch model


Chemistry Department


College of Liberal Arts and Sciences

Date Range



Physical Sciences and Mathematics


It is often the case in educational research that the impact of an educational innovation is assessed though pre and post testing. There are several ways to quantify the change in student understanding. Many of the widely used methods are based on Classical Test Theory and use students percent correct scores to determine learning gains. Issues associated with using measures based on percent correct totals will be discussed. This talk will describe how using Item Response Theory, specifically the Rasch model, as a basis for measuring change ameliorates many of the issues associated with common indicators of change in student understanding. Techniques that can be used include Differential Item Functioning (DIF), racking and stacking the data, and multidimensional Rasch models. Examples of these methods will be presented using a recently collected data set.

Conference Name

Biennial Conference on Chemical Education

Conference Location

University Park, PA

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