1. B

    DIF Analyses with Missing Data

    Hi all, I'm currently analyzing items from a bank for K-12 education. I have a separate data set for each grade/subject combination (for example, 1st grade English is a set, 2nd grade English is a set, etc). Each data set contains 400-7000(!) items. I would love to able to run various DIF...
  2. R

    Differential item functioning for IRT using R programme

    Hello, I will analyze polytomous differential item functioning for IRT. I have a Likert type scale. For example, I want to analyze items in term of gender. lordif is sufficient for this or are there any other packages in R programme? Best Regards,