EPRS9350 (Intro to IRT)


        Class.dat: N = 200, NI = 40, Dichotomous dataset (Simulated data), Class10.csv (command delimited data): N = 200, NI = 10, Dichotomous dataset (Simulated data),

        FR.dat: N = 1000, NI = 55, Dichotomous dataset (Real data)

        N411.zip (N411r.cov, N411f.cov, N411f.sco, and N411.li2):  Data files for DIF analysis

        N211R.Zip (N211r.cov, DN211f.cov, and DN211f.sco), R3F3_Polycov.zip, dn211dif.csv




        CTTITEMsas.zip:  Free CTT Item Analysis Macro in SAS, See Lei and Wu 2007

        CTTITEMspss.zip: Free CTT Item Analysis Syntax in SPSS, See Lei and Wu 2007

        CITAS.zip from Assessment Systems:  Free CTT Item Analysis in Excel. Because it is designed for classroom use, CITAS is limited to 50 items and 50 examinees.

                For more powerful classical analysis programs, Assessment Systems recommend Lertap and Iteman.

        ICC_Excel.xls: A simple, not-fancy, Excel program to plot an ICC (by Oshima), ICC_Excel_DIF.xls: To plot two ICCs to see DIF (by Oshima)

        How to simulate using Excel (by Oshima)

        SIMULA.sas: An example of SAS for simulating data (by Oshima), SimProg1.sas, SimProg2.sas : Program used in the SAS for Simulation video

       MDSIM: An example of SAS for simulating multidimensional data (by Oshima)

        IRTFIT: IRT Model Fit Software, End-User License Agreement, User's Guide (PDF), SAS Macors, Examples (zip)

        IRTDIF.zip  (IRTDIF.EXE, SAMPLE.OUT, SAMPLE1.COV, SAMPLE2.COV, Batch.txt)  by Kim and Cohen, 1991

        Equatenp.zip:  EQUATE (COMPUTER PROGRAM VERSION 2.1) by Frank B. Baker 1993

   Here are more equating programs from the University of Iowa (Center for Advanced Studies in Measurement and Assessment):

  1. PIE (for PC Console, for PC GUI, for MAC OS9, for MAC OS10)
    Conducts IRT true and observed scoring equating for dichotomously scored tests.
  2. POLYEQUATE (for PC Console, for MAC OS9)

    Conducts IRT true and observed scoring equating for dichotomously and polytomously scored tests.

IRTEQ: Windows Application that Implements IRT Scaling and Equating Version 1.1 (2011) Citation: Han, K. T. (2009). IRTEQ: Windows application that implements IRT scaling and equating [computer program]. Applied Psychological Measurement, 33(6), 491-493.

plink: An R Package for Linking Mixed-Format Tests Using IRT-Based Methods Jonathan P. Weeks, University of Colorado at Boulder. (2010) Available at: http://CRAN.R-project.org/package=plink

IRT Scale Transformation Programs (ST, PolyST) from Univerisy of Iowa PolyST

Using R: Latent Trait Models under IRT (ltm)by Dimitris Rizopoulos

difR (MAGIS, D. D., BÉLAND, S., TUERLINCKX, F., & DE BOECK, P. (2010). A general framework and an R package for the detection of dichotomous differential item functioning. Behavior Research Methods42(3), 847-862.)






        Free DIF software information

EPRS9360 (Advanced IRT)

IPLINK Program, Help File, IPLINK Help in pdf Description

DIFCUT Program Description

PolyCov: A program to compute item parameter covariances from a polytomous IRT analysis. This software is copyright (c) 2008 by Dr. Scott B. Morris

IRTGEN Program Description


DFIT8 - Manual, For the program, please email Oshima@gsu.edu