I am trying to run following command, which through an error. can some one help?
Male2PL <- mirt(mydata1[1:2651,], 1, "2PL", SE=TRUE)
Female2PL <- mirt(mydata1[2652:5352,], 1, "2PL", SE=TRUE)
Error: The following items have only one response category and cannot be estimated: Gender
data frame as follows:
Thanks in advance,