The purposes of these studies were (a) to establish on a general basis whether 3 time-honored manipulable components of punishment combine additively, or multi-plicatively in determining the judged deterrence value of a sanction, and (b) to explore the equivalence in principle of two mutually exclusive experimental designs. Study 1 used a repeated measures design whereas main and interactive effects of certainty and severity were substantial and appeared to follow a multiplying rule, celerity effects were very small and local. Studies 2a and 3 used independent groups and established that the results of Study 1 were not merely an arbitrary product of the method. The discussion addresses the minimal effects of celerity, the interaction between certainty and severity, and the theoretical implications of choice of method.