Dear R users, I am using ltm and eRm package in analysing my polytomous data for fitting item response theory and Rasch model, respectively.
I'm having a problem with the error as below; > library(eRm) > library(ltm) > HT <- read.csv("C:/Dropbox/Analysis R_2023/HT.csv") > response_columns <- HT[, 1:ncol(HT)] > response_matrix <- as.matrix(response_columns) > irt_model <- grm(response_matrix) > rasch_model <- Rasch(response_matrix) Error in Rasch(response_matrix) : could not find function "Rasch" Then I changed the arguments of Rasch to RM, but it also turns out an error as below; > rasch_model <- RM(response_matrix) Error in datcheck(X, W, mpoints, groupvec, model) : Dichotomous data matrix required! Is there any problem with the arguments or any other problem with my coding since errors keep occurring when I want to run Rasch. Thank you very much for any help given. Azi. [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.