Using the M-DIF Online Platform: A Practical Tutorial for DIF Magnitude Estimation

This article presents a practical tutorial for using the M-DIF online platform, a no-code interface designed to estimate the magnitude of Differential Item Functioning (DIF). The M-DIF approach defines DIF magnitude as the predicted difference in item difficulty between a focal group and a reference group. It integrates information from multiple established DIF detection methods together with testing-condition indicators such as group sizes and test length, providing a single continuous estimate with an accompanying uncertainty interval. To make this framework accessible to users without programming experience, we developed an interactive Shiny platform that performs magnitude estimation, visualization, and diagnostic reporting. This tutorial illustrates the platform’s core functions using a subset of data from the 2021 Progress in International Reading Literacy Study (PIRLS). Step-by-step examples guide users through uploading data, specifying groups and anchor items, adjusting visualization settings, interpreting magnitude estimates, and reviewing supplementary diagnostics. The platform offers a practical and efficient tool for researchers and practitioners who seek interpretable, magnitude-centered evidence for item review in educational and psychological assessments.