> The major problem [with STV] was that the vote set for a 3 party 3 seat > election with party preferences:
> Could be the 1st count vote distribution: > Which gives parties A, B and C one seat each. > Or > Which gives party A two seats and C one seat. > > The model takes two extreme situations one in which the first > preference vote of a party is equally divided between all the > candidates of that party, another in which one candidate of > each party has all the first preference votes. It then > calculates the result under both sets of assumptions and if > they are different decides the result using a random number. This is probably an extreme illustration of the benefits of "vote management". I know it is common in modelling exercises to assume that all electors vote "the party ticket", but that is not what a surprising number of real electors do in real elections. I have looked only at the "ballot papers" for the Meath constituency of the 2002 Dáil Éireann STV-PR election, but the voting patterns have some major lessons for party managers - and voting system modellers. There were 14 candidates for 5 seats and some 64,00 voters. The two largest parties (FF and FG) both put up 3 candidates; all the other parties put up only 1; there were also some non-party independents. FF received the most first preferences. About half of those first preferences went to one candidate. But of those who voted "1" for that candidate, only 44% voted "1", "2", "3" for FF's three candidates. 35% of those voters were "lost" at the second preference and a further 21% were lost at the third preference. Of course, many of those voters "came back" to FF at a subsequent preference, but it does show that the "party ticket" is a gross over-simplification as a model for real voter behaviour. James ---- Election-methods mailing list - see http://electorama.com/em for list info
