FreeIRT Project
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SAS macro-programs
%AnaQol
%Gammasym
%Gausshermite
%BackRasch
%LoevH
%MSP
%Detect
Stata modules
traces
raschtest
gammasym
gausshermite
mmsrm
imputeitems
imputerasch
imputemok
raschfit
backrasch
geekel2d
loevH
msp
hcavar
detect
clv
simirt
Simulated data
Coming soon
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Update:
May 5th, 2008
 
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IRT (Item Response Theory) has been undergoing important developments in the past few years. Indeed, many general purpose statistical packages still don't have procedures implementing these new indices, methods and models.

As a consequence, a significant number of specific packages have been developed by psychometricians (see http://www.assess.com). However, no package offers a comprehensive set of methods, and no package has emerged as standard tool in the field.

The increasing sophistication of general statistical packages, on the other hand, allows user-written routines to be developed which will implement IRT methods within the context of an already-familiar computing environment.

This site presents a set of macro-programs for use with Stata or SAS. While they were originally developed to analyse quality of life scales, they can, of course, be used in the area of psychometrics, test construction etc.

These macros come in the following categories:

  • Selection of items to form unidimensional scales (RASCHFIT, MSP, HCACCPROX, BACKRASCH, CLV)
  • Validation of a supposed structure of the items (DETECT, LOEVH)
  • Traces of the items (ANAQOL, TRACES)
  • Modelling (ANAQOL, GEEKEL2D, RASCHTEST, MMSRM)
  • Graphical validation (ANAQOL,RASCHTEST)
  • Tests for the Rasch model (ANAQOL, RASCHTEST)
  • Simulation of data (SIMIRT)
  • Others tools (GAMMASYM, GAUSSHERMITE)

The spirit of this web site inspired the creation of the FreeIRT Project in collaboration with Karl Bang Christensen.