rasch.prox.Rd
This function estimates the Rasch model using the PROX algorithm (cited in Wright & Stone, 1999).
rasch.prox(dat, dat.resp=1 - is.na(dat), freq=rep(1,nrow(dat)), conv=0.001, maxiter=30, progress=FALSE)
dat | An \(N \times I\) data frame of dichotomous response data. |
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dat.resp | An \(N \times I\) indicator data frame of nonmissing item responses. |
freq | A vector of frequencies (or weights) of all rows in data frame |
conv | Convergence criterion for item parameters |
maxiter | Maximum number of iterations |
progress | Display progress? |
A list with following entries
Estimated item difficulties
Estimated person abilities
Number of iterations
Item standard deviations
Person standard deviations
Wright, B., & Stone, W. (1999). Measurement Essentials. Wilmington: Wide Range.
############################################################################# # EXAMPLE 1: PROX data.read ############################################################################# data(data.read) mod <- sirt::rasch.prox( data.read ) mod$b # item difficulties