Is it possible to infer the testlet structure in a set of items using item response theory?
Specifically, I've created a lot of variations on the story recall task, each variation being scored on 25 details as passed/failed. It is clear from administering that people remember "chunks" of the stories, indicating a clear testlet structure. Thus the "plain IRT" assumption of independent items would not represent the data well. Rather than guessing, I'd like to infer the (probabilistic) testlet-membership of each item from the data.
I'm currently doing Bayesian IRT using a Rasch model and JAGS for sampling. But any thoughts on how this could be done would be appreciated.