Factor analysis with multiple responses to a question I have a data relating to a questionnaire that takes form of a knowledge test, in which each question has multiple correct responses and the respondents can check all responses they consider to be correct to a particular question. That is, the questions are "multiple response" type, to select 1+ response in each question. I wanted to perform a factor analysis on the data to psychometrically validate the questionnaire; however, I have never done a psychometric analysis on a questionnaire with multiple "positive" responses selected. Is this even possible to perform factor analysis on such data and if not is there any alternative analysis that lends itself to such data?

Factor analysis is a model to measure latent variables. Usually it is applied to questionnaire items with no right or wrong, and instead used to identify items which correlate and load onto the same factor.
Your questionnaire seems to be a test, so I would look into classical test theory instead. You can start by building sum scores, e.g. by counting the amount of correct responses.
