Economic modeling, like computable general equilibrium modeling, allows to identify markets interactions and to simulate economic behavior. The lack of formal tests to validate such models implies that seemingly good structure of a model may contain flaws that lead to unreasonable results. This paper identifies the key elements of intertemporal general equilibrium modeling omitted in the literature and provides guidance to policy modelers. Even a well designed model will not converge to a steady state if the data do not fulfill several requirements. Simulation results can be very much biased even if the model is properly calibrated. Applying several computable general equilibrium models to a single database allow us to explain and to solve selected issues. The lack of the tests to validate such models should not be a pass for unreasonable results. The paper helps to understand the source of selected "strange" results in the literature.
