[Apologies if this appears more than once; I tried to send it over 12 hours ago and it didn't appear (and isn't in the archive either) so I'm guessing it didn't get posted; I'm resending because I really could do with an answer to my questions!]
I'm trying to write an article about suitable voting systems for referenda (one proposal, which then has amendments suggested, and the vote is currently conducted using IRV). Recently there have been some potentially dubious results, and I've been looking into other methods which might be preferable. What I'd like to do is draw up a table showing which systems satisfy which criteria. I've read Mike Ossipoff's, Blake Cretney's and Stephen Eppley's websites, and find myself somewhat confused as to which criteria are the same between the webpages, and which are different. The methods I want to compare are Approval, Average Rating, Borda, IRV, Plurality and Condorcet (with assorted completion rules: CpSSD, MAM, and Tideman's Ranked Pairs at the very least, and possibly a scheme of my own devising -- of which possibly more later). The criteria I wish to compare these systems against are the Condorcet Criterion, the Independence of Clones Criterion (ICC) the Local Independence from Irrelevant Alternatives Criterion (LIIAC), the monotonicity criterion, the Smith criterion, Cretney's Secret Preferences Criterion (SPC) and Consistency Criterion, Ossipoff's Generalised Strategy-Free Criterion (GSFC), Strong Defensive Strategy Criterion (SDSC) and Weak Defensive Strategy Criterion (WDSC). Some of these have different names on Eppley's pages. I'd appreciate corrections on the following beliefs: 1). Approval and Average Rating meet ICC, Consistency Criterion, monotonicity and WDSC, fail SDSC and GSFC, and the other criteria are either irrelevant or failed. 2). Borda meets only Consistency Criterion and monotonicity and fails the rest. 3). IRV meets only ICC and SPC. 4). Plurality meets consistency and SPC (although that could be argued to be irrelevant); the other criteria are either irrelevant or failed. 5). All the Condorcet methods meet the Condorcet Criterion, ICC, LIIAC, monotonicity, the Smith Criterion and GSFC, and fail the Consistency Criterion and SPC. I've read that Tideman's Ranked Pairs fails SDSC and WDSC, but the other two completion methods meet them. Am some (or all) of these beliefs incorrect? I'd be very grateful for any help that people could give me. Diana. ---- Election-methods mailing list - see http://electorama.com/em for list info
