IRTDIF swMATH ID: 37277 Software Authors: S. Kim, A. Cohen Description: IRTDIF: A Computer Program for IRT Differential Item Functioning Analysis. RT models. To compute the DIF measures and the statistics to test the significance of the DIF measures, IRTDIF uses two files. One file contains sets of item parameter estimates; the other contains the sampling variance-covariance matrices. Significance levels (p values) are provided for Lord’s x2 and the exact area measures. When the sampling variance-covariance matrices are not available, the exact and closedinterval area measures are provided without statistical significance tests. The program was written in IBM Professional FORTRAN for IBM and compatible personal computers and uses subroutines taken from Numerical Recipes (Press, Flannery, Teukolsky, & Vetterling, 1986) to compute the percentage points of the incomplete gamma functions. Execution of the program requires a numerical coprocessor Homepage: https://www.umass.edu/remp/software/CEA-652.ZH-IRTSoftware.pdf Dependencies: FORTRAN Related Software: BILOG; ConQuest; IRTLRDIF; DICHODIF; DFITPU; DIFAS; SIBTEST; difR; lordif; R; deltaPlotR Cited in: 0 Publications