read.ip.icl: Read in parameter estimates
Description
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.
Value
A list with two elements, est and se, for
the parameter estimates and their standard errors,
correspondingly. Because ICL does not compute standard
errors, se 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.