Social Choice Observed: Five Presidential Elections of the American Psychological Association

There have been few opportunities to assess the implications of social choice theory using data from large, naturally occurring elections. We examine here five presidential elections of the American Psychological Association. These elections involve ten to fifteen thousand voters who express rank-ordered preferences over five candidates. We investigate the occurrence of the "paradox of voting," the ability of various voting systems to select majority winners, violations of subset rationality conditions, and the possibility of manipulating election outcomes through the misrepresentation of preferences. The frequent occurrence of these anomalies (with the exception of the paradox of voting) emphasizes the essential relevance of social choice theory to a theory of democratic electoral processes.