I am testing competing hypotheses where one hypothesis contains a mediation effects that can be modeled using a path model. The other hypothesis does not include a mediation effect and therefore can be modeled using a simple linear regression. Both models will be run using the same dataset and will have the response variable (or exogenous variable in the path model's case). Therefore, I am wondering if it is appropriate to utilize AIC to compare/rank these models? The path model is being built using the piecewiseSEM package. I have read papers where they have used AIC selection for different path models but never a case when comparing a path model to a non-path model.
Any thoughts would be appreciated.