Voting and Elections: Introduction

Posted October 2004.

Feature Column Archive

1. Introduction



Everyone is familiar with the power of mathematics to solve problems in physics. Though Galileo is recognized more as a physicist than a mathematician, he was a professor of mathematics at the University of Pisa (1589-1591) and the University of Padua (1592-1610). Isaac Newton (1642-1727) makes any short list of both the greatest physicists and mathematicians of all time. Other mathematicians who made significant contributions to mathematics and physics include Leonard Euler (1707-1783), Laplace (1749-1827), and Gauss (1777-1855).



Mathematics has also had an important role to play in chemistry, geology and biology but what about mathematics and political science? Has mathematics had significant applications in political science? I believe so and in my discussion here I will deal with mathematical approaches to voting and elections. Contributions of mathematics to voting began earlier than many people realize. During the period of the French Revolution, two fascinating people with talent in mathematics, the Marquis de Condorcet (1743-1794) and Jean de Charles Borda (1733-1799), raised important ideas related to voting systems. Others who made contributions to mathematical ideas that involve elections include Charles Dodgson (1832-1898), Duncan Black (1908-1991), Kenneth Arrow, and John Kemeny (1926-1992), and Steven Brams. Dodgson was a professional mathematician at Oxford, in addition to being the author of Alice in Wonderland. Duncan Black was an economist who revived interest in using mathematical tools to study voting systems. Black's book The Theory of Committees and Elections revived significant interest in using mathematical tools to study election questions. Arrow, though he taught in economics departments, began his academic career as a mathematics major. Kenneth Arrow won the Nobel Memorial Prize in Economics in 1972 in part for the insight he obtained into group decision making processes in his 1951 doctoral dissertation.



Marquis de Condorcet

Jean Borda

Charles Dodgson

John Kemeny

The images above are available with permission from the The MacTutor History of Mathematics archive at the University of St Andrews, Scotland



If one is to do a mathematical analysis of any subject, one has to carefully examine phenomena related to what one is investigating and make simplifying assumptions, to construct what today are called mathematical models. Voting is carried out in a surprisingly large array of situations: selection of candidates for municipal, state, and national elections; votes that legislators make when choosing among alternative courses of action; decisions by economic planners about what course of action to take; selection by judges of the winner for a skating competition; selection of a movie for best film of the year; or selection of what should be served at the company picnic. What are the salient phenomena involved in elections and voting? Elections require voters and alternatives to choose from (typically people, but there are many other possibilities). To express voter opinions about the alternatives requires a ballot of some kind. After the voters make their judgments on the alternatives (candidates), it is required that some decision method be used to arrive at the winning candidate, winning candidates, or a collection of selected alternatives.



There are many interesting aspects of elections that probably will not play a part in a first pass at using mathematics to study elections. Should felons be restricted from voting? Should people who can not be present when the voting is to take place have a way to cast a ballot in some other way? Are the machines (or physical mechanism) currently used for voting the best choice possible? (Best choice from what point of view?)