2013/6/6 Abd ul-Rahman Lomax <a...@lomaxdesign.com> > Another issue that was left a bit hanging in discussions on the CES list: > > Does top-two Approval fail the Favorite Betrayal Criterion? There are > really two forms of top-two Approval to be considered, plus a third detail. > > 1. Top two approval where two candidates advance to the general election. >
This fails FBC. I am sympathetic to Abd's arguments about how the electorate will change based on preference strength, and how well-informed voters will tend to find a way to avoid FBC failure, but that doesn't mean that it passes the criterion, merely that the failure is minor. > 2. Top two approval where a candidate with a majority can win, otherwise > two candidates advance. > Still fails, although it's slightly better. > 3. If write-in votes are allowed in the runoff, the primary is actually a > nomination device, not the actual election. The actual election being > Approval, the combination must satisfy FBC if Approval does, and it does. > This is true... but only if there's a hard threshold for making it to the second round. That is, "all candidates with over 1/3 approval advance", or some such; and if there are fewer than 2 such candidates, the highest approval wins in the first round. > (If write-in votes are allowed, in this concept, the runoff must also be > Approval.) > > Arizona had a method up for legislative passage that would have allowed > municipalities to use a two-stage voting system with an Approval primary, > top-two advancing to the general election with ballot placement, and, > apparently, write-ins allowed in the general election (as well as in the > primary). The primary has no majority test, it is top-two plurality, but > voters may vote for as many candidates as they choose. The runoff is > standard vote-for-one. > > So, first of all, does this method fail FBC? If so, is the scenario > plausible for real voters? These are nonpartisan elections. > > > ---- > Election-Methods mailing list - see http://electorama.com/em for list info >
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