Dear folks, earlier this year Forest and I submitted an article to Social Choice and Welfare (http://www.fair-chair.de/some_chance_for_consensus.pdf) describing a very simple democratic method to achieve consensus:
> Simple Efficient Consensus (SEC): > ================================= > > 1. Each voter casts two plurality-style ballots: > A "consensus ballot" which she puts into the "consensus urn", > and a "favourite ballot" put into the "favourites urn". > > 2. If all ballots in the "consensus urn" have the same option ticked, > that option wins. > > 3. Otherwise, a ballot drawn at random from the "favourites urn" > decides. This method (called the "basic method" in our paper) solves the problem of how to... > make sure option C is elected in the following situation: > > a% having true utilities A(100) > C(alpha) > B(0), > b% having true utilities B(100) > C(beta) > A(0). > > with a+b=100 and a*alpha + b*beta > max(a,b)*100. > (The latter condition means C has the largest total utility.) Since then I looked somewhat into spatial models of preferences and found that also in traditional spatial models, our method has the nice property of leading to a very quick maximization of total utility (the most popular utilitarian measure of social welfare): Assume the following very common spatial model of preferences: Each voter and each option has a certain position in an n-dimensional issue space, and the utility a voter assigns to an option is the negative squared distance between their respective positions. Also assume that voters can nominate additional options for any "in-between" position (to be mathematically precise, any position in the convex hull of the positions of the original options). Traditional theory shows that, given a set of voters and options with their positions, total utility is maximized by the option closest to the mean voter position, but many traditional voting methods fail or struggle to make sure this option is picked. With our method SEC, however, total utility will be maximized very quickly: If the "optimal" option X located at the mean voter position is already nominated, every voter will have an incentive to tick X on her "consensus ballot" since she will prefer X to the otherwise realized fall-back lottery that picks the favourite of a randomly drawn voter. If X is not already nominated, every voter will have an incentive to nominate X for the same reason. This makes sure X is elected and thus total utility is maximized. Yours, Jobst ---- Election-Methods mailing list - see http://electorama.com/em for list info
