Hi all, I am fitting my model to a data. The data is from 30 participants and each participant has 300 trials. I have 2 parameters in my model. One of them is going to be for every subject. So i have 300 trials for this parameters for each participant. But the other parameter is different for every participant and every trial of each participant, so it would have 30*300 quantities after fitting. I have only one observation for every quantity. The important point is that the second parameter is not important for me and i want to know the quantities of the first parameter. My question is that; does using the first parameter makes the quantities for first parameter unreliable? or if i want to compare two models that both of them have the second parameter , does the BIC`s are reliable for model comparison?

My problem until know is that i can see the effect of my data in generated quantities produced by fitting but i cannot see the effect from simulation when i use the fitted parameters for simulation.