> The study of voting systems has made significant progress over > the last > decade, and our understanding is even farther beyond what it was > 20 years > ago. One important place where that has happened is on the > election methods > mailing list. This mailing list is likely to include the largest > and most > diverse group of voting systems theorists in the world. It is a > place where > opinions vary and debate is vigorous. Thus, we think that the > broad, though > imperfect, consensus on the following ideas is worth paying > attention to. > > We believe that the voting systems currently used in most of the > English-speaking world, including single-round plurality voting > (also termed > First Past the Post, FPTP) and single-member districts (aka > seats, ridings, > or electorates), represent some of the worst voting systems > known. We > believe that reforming these systems would provide important societal > benefits, and that there are clearly not corresponding reasons > to oppose > such reform from the perspective of the public interest. We may > disagreeabout which specific reforms might provide the > absolutely optimum results, > but we can nevertheless agree that there are a number of options > which would > represent worthwhile improvements. > > *Single-winner reform* > > There are various criteria, both formally-defined and informal, > by which one > can judge a voting system. These criteria can be divided into several > classes: > > 1. Honest-results-oriented criteria. These include such measures > as Bayesian > regret (that is, simulated societal satisfaction), the majority > criterion,and the Condorcet criterion, which focus on whether > the "correct" candidate, > according to some definition, is elected. Although these > criteria in some > cases can favor different candidates as being "correct", in most > practicalcases they agree. > > 2. Strategy-resistance criteria. Voting is a complex process, > and inevitably > there are some cases where some group could get an advantage by > changingtheir votes. It is desirable to keep such cases to a > minimum. For one > thing, it's fairer not to reward such strategic voting behavior. > But it's > not just that. Perhaps more importantly, a voting system which > gives too > much of an incentive to strategic voters, can lead to widespread > strategywhich systematically distorts the results. > > 3. Process-oriented criteria. These include such measures as > simplicity of > the ballot, simplicity of the ballot-counting process, and > feasibility of > auditing or other fraud-prevention measures. > > 4. Candidate-incentive criteria. Systems which encourage or discourage > "clone candidates"; give too much power to parties, as opposed > to voters; > have problems here. These criteria also include less strictly-defined > concerns about the type of candidates and campaign strategies a system > encourages; for instance, systems which effectively reduce the > field to 2 > major candidates could encourage negative advertising. > > There is a broad consensus among researchers plurality voting is > among the > worst systems for honest results, for strategy-resistance, and > for candidate > incentives. Honest voting can split votes among similar candidates, > "spoiling" the election and leading opposing candidates to win. Voters > respond by strategically choosing the "lesser evil" among the > two major > candidates, which can lead to complacent candidates because even > corrupt,widely-disliked candidates can win. The system > discourages candidates from > entering the race, and encourages negative advertising. Although > pluralityhas good simplicity and fraud-resistance, this is not > enough to recommend > its use. > > A number of proposed single-winner replacements for plurality exist. > Although theorists can not find consensus about which of these > systems is > best, we can agree that many of them are clearly head-and- > shoulders above > plurality. Systems advanced as as best by some of us, and > accepted as good > by all of us, include (in categorical and alphabetical order): >
Put Approval Voting here in alphabetical order, and mention that each of the following methods is a generalization of Approval in a slightly different direction. In other words all of the most highly esteemed methods on the EM list turn out to be generalizations of Approval I know that you made this point in a slightly different way, but it could easily be passed over without registering mentally if we are not careful. > - Various *Bucklin* or median-based systems such as *Majority > Judgment* - Various *Condorcet* systems, including > *Condorcet//Approval, various > Condorcet//IRV hybrids, Ranked Pairs, *and* Schulze*. > - *Range Voting* (aka Score Voting) > - *SODA voting* > > Notably absent from the above list is IRV (aka Alternative Vote, ---- Election-Methods mailing list - see http://electorama.com/em for list info
