I have set of capture histories with some information on breeding status (non-breeders/successful breeders/failed breeders) which I can choose to model as separate states when estimating survival, or combine breeders, or adults, into a single event and/or state, for example. I understand this choice will also depend on the exact parameters requiring estimation and the hypothesis that might be tested, but assuming this makes no difference and I could model either way, would comparing AIC of two models with different fundamental structures be valid? (i.e. to see which might be the better approach)

To my understanding, AIC is normally compared between two models that differ in their GEMACO model definition, for example with time variant or time constant survival. At what point does it become an invalid comparison of AIC? If only GEPAT matrices have parameters/transitions specified differently? If GEPAT matrices have different steps? If only the events are coded differently from the data? If underlying states are defined differently?

Given that the AIC derives from the likelihood, which is the probability of the data given the model parameters, are comparisons valid in all variations of parameter definition and model structure except where the raw data changes? And would therefore coding a set of capture histories differently in two models constitute changing the raw data and make AIC not comparable, in the same way as changing the set of capture histories (which is surely not comparable)?

Thanks for any opinions or advice!