Rational agents are the quickest

We consider agents who choose by proceeding through a checklist of criteria (for any pair of alternatives the …rst criterion that ranks the pair determines the agent’s choice). Regardless of the discriminating capacity of the criteria in a checklist, choices that maximize complete and transitive preferences can always be the outcome of a ‘quick’checklist that uses a small number of criteria. For any irrational preference on the other hand there is always a discriminatory capacity for criteria such that the preference is not the outcome of a quick checklist. Moreover, if we …x the discriminatory capacity then, as the size of the domain increases, the proportion of irrational preferences that can be the outcome of a quick checklist goes to 0 at a super-exponential rate. We also show that checklists that can be assembled at lowest cost always lead to rational preferences. JEL codes: D01