Probabilities of election outcomes with two parameters: The relative impact of unifying and polarizing candidates

Consider an election on three candidates for n voters with complete and transitive preference rankings on the candidates. Let k (r) denote the minimum total number of last (middle) position rankings for each of the three candidates. If k is close to zero, some candidate is seldom disliked and is a unifying candidate. If r is close to zero, some candidate is always either liked or disliked and is a polarizing candidate. A procedure is developed to obtain representations for conditional probabilities of election outcomes, when parameters like k or r are specified. Representations are obtained for the conditional probability that a pairwise majority rule winner, or PMRW, exists, given k and given r. Results show significant differences in the impact that unifying and polarizing candidates have on the probability that a PMRW exists. Copyright Springer-Verlag Berlin/Heidelberg 2005