From ICL output, read in estimates of item parameters. Invoked automatically
when the model is estimated via irtoys. If that is not the case,
file must be a file produced with the write_item_param file
command in ICL.
read.ip.icl(file)File name
A list with three elements, est, se, vcm for the parameter
estimates, their standard errors, and the variance-covariance matrix per item.
Because ICL does not
compute standard errors, se and vcm will be NULL. est is a matrix with
one row per item, and three columns: [,1] item
discrimination \(a\), [,2] item difficulty \(b\), and [,3] asymptote
\(c\). For the 1PL and 2PL models, all asymptotes are equal to 0; for the
1PL, the discriminations are all equal but not necessarily equal to 1.