Although the homo oeconomicus model has considerable predictive power with regard to the operation of the law the assumption of strict (unbounded) rationality creates opposition on the side of the legal profession. Drawing on Ronald Heiner's theory of imperfect decisionmaking the model of a boundedly rational decisionmaker is developed. Due to a competence difficulty gap a boundedly rational decisionmaker can commit two types of errors well known from statistical decisiontheory. The paper discusses the ways of rationally controlling decision errors and derives some consequences regarding crime and punishment.