Included for those who are too faint-hearted to write
as.matrix(read.table(file, head=F)). Of course,
data can be entered into R in many other ways. The data values in the file must be separated with
blanks.
Responses are the empirical data used in IRT. Note that
irtoys deals with models for dichotomous data, and
typically expects data consisting of zeroes and ones,
without any missing values (non-responses are considered
as wrong responses). In fact, there are only two commands
in irtoys that accept other kinds of data:
sco and tgp.
read.resp does accept missing data and values
other than 0 and 1. Use sco and a key to score
multiple choice responses to 0/1. If you have dichotomous
data that contains NAs, you can use sco without a
key to change all NA to 0.