read.ip.bilog: Read in parameter estimates
Description
From BILOG 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 >SAVE PARm file;
command in BILOG.
Value
A list with two elements, est and se, for
the parameter estimates and their standard errors,
correspondingly. Each element 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.