Error in gauher(k) : object 'gh' not found using difGenLord function

user_10341381 0
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I have a data frame of 111 items with a binary answer (0 for failure, 1 for success) followed by a column with the Group (named Group and coded with 1, 2 or 3). I have 145 rows (subjects) + the heading.

I am trying to screen for differential item functioning in the 3 different groups of subject (1,2 or 3) thanks to the difR package.

My dataframe is Nam, here is the code i used :

    Mat<-data.matrix(Nam, rownames.force = NA) 
    res<-difGenLord(Mat,group="Group",focal.names="2,3",nrFocal=2,model="1PL")
    Error in gauher(k) : object 'gh' not found

I did not find anyone reporting the same error and I am stuck with this problem. Anyone has an idea what gauher(k) is supposed to be ?

error-handling r
2 Answers

I encountered the same problem. I think gauher(k) is a hidden function in the ltm package. For me simply loading the ltm package by hand with library(ltm) solved the problem. Hope it helps you too!

user_104614140

I just had the same problem. and solved by adding the following hidden function. 

library(ltm)
library(lme4)
user_111872140
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