Knowledge that Transforms

We develop and test a model of social duties. The model distinguishes unconditional duties to take or avoid certain actions from conditional duties that depend on the actions’ payoffs. It also distinguishes strict duties (must do) from liberal duties (ought to do). The disutility associated with duty violation depends on the duty’s strictness and is proportional to the externality the violation causes. The model rationalizes behavioral patterns that are incompatible with consequentialist preferences. Our tests comprise parameter estimation based on subjects’ behavior across different situations as well as measurement of duties through spectators’ appropriateness ratings.

Many ideas succeed in small trials but weaken considerably at scale. Using early childhood investment as a case study, this paper develops a dynamic microfounded human capital model stylized in the Chicago tradition. The framework features optimizing agents, complementary skill formation, and a policymaker choosing scaling strategies. The model shows that naive extrapolation from pilots systematically overestimates societal impact by overlooking voltage drops: declining benefit-cost profiles due to unrepresentative samples and contexts. Optimal scaling requires option C thinking, a mechanism-based design approach that anticipates these failures through backward induction from real-world implementation constraints. Studies in this special issue enrich the model’s insights.