In a statewide achievement test, the use of a calculator is often allowed as an accommodation for students with disabilities (SWD). The purpose of the accommodation is to eliminate the disadvantage faced by SWDs relative to peers without disabilities with the same level of overall mathematics proficiency. However, it is important to determine if the accommodation has changed the construct and meaning of the test scores. One way of examining whether the construct has changed due to the accommodation is to compare performance on the assessment for SWDs to peers without disabilities, controlling for differences in proficiency. In this study, measurement invariance of a statewide 8th-grade mathematics test was explored to evaluate the comparability of the scores obtained by examinees who were accommodated with calculators and those who were not. Structural equation modeling (SEM) was used to assess measurement invariance at the content strand level. Also, nonlinear factor analysis (NFLA) was used to assess the invariance at the item level and the solution was compared to the SEM results. Results indicate the accommodation tended to make items in the content strand Number Sense and Operations easier. The relative strengths and limitations of using SEM and NLFA to evaluate test accommodations is discussed.
Lee, Minji Kang; Wells, Craig S.; and Sireci, Stephen G., "A Comparison of Linear and Nonlinear Factor Analysis in Examining the Effect of a Calculator Accommodation on Math Performance" (2010). NERA Conference Proceedings 2010. 10.