The IFORS Distinguished Lecturer for the INFORMS meeting was Michel Balinski of Ecole Polytechnique and CNRS, Paris. Michel spoke on “One-Vote, One-Value: The Majority Judgement”, a topic close to my heart. In the talk, Michel began by discussing the pitfalls of standard voting (manipulation, “unfair” winners, and so on). He then spent most of his talk on a method he proposes for generating rankings and winners. For an election on many candidates (or a ranking of many gymnasts, or an evaluation of many wines: the applications are endless), have the electors (judges, etc.) rate each candidate on a scale using terms that are commonly understood. So a candidate for president might be “Excellent, Very Good, Good, Acceptable, Reject”. Then, the evaluation of a candidate is simply the median evaluation of the electors. The use of median is critical: this limits the amount of manipulation a voter can do. If I like a candidate, there is limited effect if I greatly overstate my liking: it cannot change the overall evaluation unless my evaluation is already under that of the median voter.
Michel then went on and discussed some tiebreaking rules (to handle the case that two or more candidates are, say “Very Good” and none “Excellent”). I found the tie-breaking rules less immediately appealing, but I need to think about these more.
Michel had done an experiment on this by asking INFORMS participants to do an evaluation of possible US Presidential candidates (not just Obama and McCain, but also Clinton, Powell, and a number of others). The result (on a small 129 voter sample) put Obama well ahead, but I do suspect some selection bias at work.
This work will be the basis of a book to be published at the end of the year, and there is a patent pending on the voting system (which I found a little strange: what would it mean to use a patented voting system?).
I didn’t get the URLs at the end of the talk. If anyone got them, can you email me with them? A quick web search only confused me more.
Added Oct 20. Michel Balinski kindly wrote and provided the following references:
Michel Balinski and Rida Laraki, “Le jugement majoritaire : l’expérience d’Orsay,” Commentaire no. 118, été 2007, pp. 413-419.
One-Value, One-Vote: Measuring, Electing, and Ranking (tentative title), to appear 2009.
Michel Balinski et Rida Laraki, A theory of measuring, electing and ranking,
Proceeding of the National Academy of Sciences USA, May 22, 2007, vol. 104, no. 21, pp. 8720-8725.
Michel Balinski et Rida Laraki, “Election by Majority Judgement: Experimental Evidence.”
Cahier du Laboratoire d’Econométrie de l’Ecole Polytechnique, December 2007, n° 2007-28