Summary
This research report investigates the predictive validity of the IXL Flex Diagnostic in relation to the Illinois Assessment of Readiness (IAR) for students in grades 3 through 8. The study aims to assess the correlation between scores on the IXL Flex Diagnostic and the IAR, as well as the degree of overlap in proficiency classifications between the two assessments. The report details the methodology, which includes analyzing data from a large suburban Illinois school district, and presents findings that indicate strong positive correlations between the IXL Flex Diagnostic and IAR performance. Specifically, correlation values for math scores range from .73 to .79, while ELA scores range from .75 to .80. The report also highlights the sensitivity and specificity of the IXL Flex Diagnostic in classifying student proficiency, demonstrating a high degree of accuracy in predicting proficiency status on the IAR. These findings support the use of the IXL Flex Diagnostic as a reliable measure of student knowledge levels in math and ELA.
