John B. Hodges wrote: > Looking at back issues of the digest of this list, I've read Rob > LeGrand's posts about Borda Elimination, which he calls Baldwin. I > gather that he's talking about a single-winner method that reliably > picks a Condorcet winner when one exists, but turns out not to be > cloneproof.
That's correct. I call it Baldwin, even though some call it Nanson, since another method is often called Nanson. I explain the difference at http://www.onr.com/user/honky98/rbvote/desc.html . > I'd like to learn more about this method, and its problems. How does > non-cloneproofness manifest? Any illustrative examples handy? Here's an example that shows that Baldwin fails clone-independence: 20:A>B>C 17:B>C>A 13:C>A>B Baldwin eliminates C and chooses A. What what if a clone of A also ran? Let's call him . . . D. 20:D>A>B>C 17:B>C>A>D 13:C>A>D>B Now Baldwin eliminates B, eliminates D and chooses C. So adding a clone of A changed the winner from A to C. This example also shows that Black, Borda and Bucklin fail clone-independence. All three pick B before adding D and A after. You can try this example at http://www.onr.com/user/honky98/rbvote/calc.html ; enter the election with all four candidates and enter D in the "candidates to ignore" box. Examine the results, then go back and remove D from the ignore list. ===== Rob LeGrand, psephologist [EMAIL PROTECTED] Citizens for Approval Voting http://www.approvalvoting.org/ __________________________________ Do you Yahoo!? Yahoo! SiteBuilder - Free, easy-to-use web site design software http://sitebuilder.yahoo.com ---- Election-methods mailing list - see http://electorama.com/em for list info
