Psychometric Principles in Measurement for Geoscience Education Research: A Climate Change Example

Abstract:

Understanding learning in geoscience classrooms requires that we use valid and reliable instruments aligned with intended learning outcomes. Nearly one hundred instruments assessing conceptual understanding in undergraduate science and engineering classrooms (often called concept inventories) have been published and are actively being used to investigate learning. The techniques used to develop these instruments vary widely, often with little attention to psychometric principles of measurement. This paper will discuss the importance of using psychometric principles to design, evaluate, and revise research instruments, with particular attention to the validity and reliability steps that must be undertaken to ensure that research instruments are providing meaningful measurement. An example from a climate change inventory developed by the authors will be used to exemplify the importance of validity and reliability, including the value of item response theory for instrument development. A 24-item instrument was developed based on published items, conceptions research, and instructor experience. Rasch analysis of over 1000 responses provided evidence for the removal of 5 items for misfit and one item for potential bias as measured via differential item functioning. The resulting 18-item instrument can be considered a valid and reliable measure based on pre- and post-implementation metrics. Consideration of the relationship between respondent demographics and concept inventory scores provides unique insight into the relationship between gender, religiosity, values and climate change understanding.