Before revision: Empirical demand models used for counterfactual predictions and welfare analysis must be rationalizable , i.e. theoretically consistent with utility maximization by heterogeneous consumers.
After revision: An important goal of empirical demand analysis is choice and welfare prediction on counterfactual budget sets arising from potential policy-interventions. Such predictions are more credible when made without arbitrary functional-form/distributional assumptions, and instead based solely on economic rationality , i.e. theoretically consistent with utility maximization by heterogeneous consumers.