I've been trying to find any references which have discussed the legitimacy of any item aggregation methods prior to conducting CFA, but I'm coming up short. Here's my context:
Large survey with 6 scenarios, 12 items per scenario, and roughly 4 items per scenario which map to 1 of 3 latent factors [see figure 1]. When I run CFA where latent factors map to each induvial item and add a method factor for each set of items within a scenario, I get marginally decent or bad fit statistics.
However, if I first sum the related items in each scenario [see figure 2], this new model produces really fantastic fit statistics. Is this type of aggregation ever allowed? If so, when is this allowed, and when is it not allowed? Why? And where are the references that talk about this?
Thanks for your help!
