The calculus of voting: An empirical test

According to the rational choice model, the calculus of voting takes the form of the equation R = BP - C, where the net rewards for voting (R) are a function of the instrumental benefits from the preferred outcome compared to others (B) and the probability (P) of casting the decisive vote that secures these benefits, minus the costs of becoming informed and going to the polls (C). Here, we provide a systematic test of this model. The analysis relies on two surveys, conducted during the 1995 Quebec referendum and the 1996 British Columbia provincial election, in which very specific questions measured each element of the model. As well, this study incorporates two other factors that can affect the propensity to vote - respondents' level of political interest and their sense of duty. We find that B, P, and C each matter, but only among those with a relatively weak sense of duty. The feeling that one has a moral obligation to vote is the most powerful motivation to go to the polls. We conclude that the rational choice model is useful, but only in explaining behaviour at the margins of this important norm.