Use of a Construct Map and Rasch Analysis in Assessing Student Understanding of Chemistry Concepts

Ideally, assessments provide information that can be used to evaluate student knowledge and influence instruction. The information provided by many common forms of assessment is limited to a percent correct score. While this provides some information, these scores are silent on the specific content or objectives the students are able to do. This talk will describe a process of assessment development that can provide an instructor or researcher with a richer description of students understanding of chemistry concepts than traditional assessments. The first step in the process is the development of a thorough definition of the construct being to be assessed. This definition can take the form of a learning progression or a construct map. Once developed, this map guides the design and/or selection of items for the assessment. The results of the assessment are then interpreted using the Rasch model, which allows the students specific content knowledge to be evaluated using the map or learning progression. An assessment developed in this manner provides results that are more interpretable than a simple percent correct score. This process of will be illustrated with a discussion of some recent research using the Bonding, Structure, and Polarity Assessment (BSPA) and its associated construct map