Examining the psychometric functionality of the force concept inventory

Abstract

To improve the current understanding of the Force Concept Inventory (FCI), both a response-option-level analysis and a dimensionality analysis were proposed and applied. The response-option-level analysis used polytomous item response theory to reveal that the response options on the FCI are generally functioning appropriately, with two questions being identified as likely malfunctioning. To address the question of the FCI's dimensionality, an analysis of local item independence using item response theory was proposed and performed. Results indicate that the FCI is a multi-factor instrument, not a unidimensional instrument as it is often assumed. As a result of this analysis, three factor models were proposed and tested using confirmatory factor analysis and confirmatory multi-trait item response theory. All of these models were found to adequately explain the factor structure of the FCI within each of the statistical frameworks. The results from these investigations can be used as a starting point for further analysis and directing future improvements of the FCI.