The introduction of decision making under uncertainty by Ferejohn and Fiorina is an interesting addition to the literature on rational theories of citizen participation. Decision making under uncertainty assumes, however, that the actor has no knowledge of the probabilities of the various outcomes; this is obviously no more true than the assumption of perfect information about these probabilities made in the decision making under risk model. Voters have some, but not perfect, information about the probabilities of at least some of the different possible outcomes.

Specifically, let us look at the two-party case. In Ferejohn's notation, (p3 + p4) is the probability of an individual's vote making a difference. We might expect a rational citizen to know that this probability is at most minuscule, even if he cannot calculate its exact value.