> [EMAIL PROTECTED] > Sent: 20 April 2007 19:17 > Optimal strategy in PR-STV is to rank all the candidates
This is optimal only if you genuinely have preferences among all the candidates. Voters should always be encouraged to mark as many preferences as they have, but they should never be advised (or forced!!) to mark preferences they do not have. When a voter leaves some candidates blank (truncates), what that voter is saying to the returning officer is: "If it comes to a choice among the candidates I've left blank, I'm out. I am happy to leave that decision to those voters who do have preferences among those candidates". Of course, a voter may have some high order preferences, and a real dislike for one or more candidates, but no preference at all AMONG the others, but they are obviously below the high order and above the disliked. In that situation that voter should, of course, mark the high order preferences, put the disliked ones last and put the indifferent ones in any order just to fill the spaces and ensure a continuous sequence of preferences. I've done that myself in real STV-PR elections! > (actually all bar 1). This makes no difference to the result, i.e. the winners. But it can make a difference to the appearance of the result sheet if the counting rules specify that all votes must be transferred, i.e. even AFTER the required number of winners has been identified. Then the effect of a 'last preference' and 'last blank' is different - the 'last blank' becomes non-transferable. This is what will happen under the STV counting rules we shall use for the local government elections here in Scotland next month when the votes are counted electronically. If a manual count is employed (a contingency provision!), the transfers are stopped when the all the places have been filled. Personally, I think transferring all possible votes after the winners have identified in real public elections is completely pointless, but I didn't write the election rules. It was a case of "Because we can, we shall", which is rarely a sound basis for good policy or good practice. James Gilmour ---- election-methods mailing list - see http://electorama.com/em for list info
