Package to fit diffusionbased IRT models to response and response time data. Models are fit using marginal maximum likelihood. Parameter restrictions (fixed value and equality constraints) are possible. In addition, factor scores (person drift rate and person boundary separation) can be estimated. Model fit assessment tools are also available. The traditional diffusion model can be estimated as well.
Author  Dylan Molenaar 
Date of publication  20150814 00:20:21 
Maintainer  Dylan Molenaar <d.molenaar@uva.nl> 
License  GPL2 
Version  1.5 
Package repository  View on CRAN 
Installation  Install the latest version of this package by entering the following in R:

All man pages Function index File listing
Man pages  

anova: Conduct a likelihood ratio test on two nested 'diffIRT'...  
brightness: A Simulated Response Time Dataset according to an...  
coef: Return estimated parameters  
diffIRT: Fitting diffusion IRT models  
extraversion: Responses and Response Times to 10 Extraversion Items  
factest: Estimating factor scores for diffIRT models  
QQdiff: Assessing diffIRT model fit for the response times using...  
RespFit: Assessing diffIRT model fit for the responses using limited...  
rotation: Responses and Response Times to 10 Mental Rotation Items  
simdiff: Simulate data according to the Ddiffusion or Qdiffusion IRT...  
simdiffT: Simulate data according to the traditional diffusion model.  
summary: Summary function for diffIRT objects 
Functions 

Files  

inst
 
inst/CITATION
 
src
 
src/diffIRT.c
 
NAMESPACE
 
data
 
data/brightness.rda
 
data/rotation.rda
 
data/extraversion.rda
 
R
 
R/coef.diffIRT.r  
R/mdiffIRT.r  
R/fitObs.r  
R/logLik.diffIRT.r  
R/fitCumChoose.r  
R/qdiffIRT.r  
R/anova.diffIRT.r  
R/likelihood.r  
R/RespFit.r  
R/fitOrders.r  
R/simdiffT.r  
R/calcSubjLL.r  
R/calcEZ.r  
R/print.diffIRT.r  
R/nobs.diffIRT.r  
R/print.RespFit.r  
R/vcov.diffIRT.r  
R/summary.diffIRT.r  
R/QQdiff.r  
R/fitDeriv.r  
R/LLscoreVd.r  
R/fitItems.r  
R/get.start.r  
R/fitPred.r  
R/deriv.r  
R/simdiff.r  
R/diffIRT.r  
R/LLscoreA.r  
R/LLscoreVq.r  
R/summary.RespFit.r  
R/pdiffIRT.r  
R/factest.r  
MD5
 
DESCRIPTION
 
man
 
man/diffIRT.Rd  
man/anova.Rd  
man/QQdiff.Rd  
man/brightness.Rd  
man/RespFit.Rd  
man/extraversion.Rd  
man/factest.Rd  
man/simdiffT.Rd  
man/rotation.Rd  
man/coef.Rd  
man/summary.Rd  
man/simdiff.Rd 
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