i just got offa the phone with a Dr. Tideman. you guys might know him. could someone here, who is more qualified than me, put in a new line into this table at Wikipedia: https://en.wikipedia.org/wiki/Comparison_of_electoral_systems#Compliance_of_selected_single-winner_methods for BTR-STV ? https://electowiki.org/wiki/Bottom-Two-Runoff_IRV I know that BTR is Condorcet-compliant (which means that it cannot be LNH) and that, strictly, it's not precinct summable (if there was a cycle, you don't know from the summable defeat data who wins). But I am not qualified to get the facts and authoritatively evaluate each criterion and say "yea" or "nay" to it. geez, i can't pay you, but i can beg. -- r b-j rbj@audioimagination.com "Imagination is more important than knowledge." . . .

Wikipedia editors require notability. Can you point to a peer-reviewed academic article or two that establishes Bottom-Two-Runoff IRV as notable? I'm not necessarily offering to do the edit because I already push the Wikipedia boundaries in other ways that I think are more important. Yet I think references would help justify whoever does have time to do the edit. Also what would help is to add to the Electowiki article a section that lists the important criteria. And asking here about which criteria you aren't sure of would make it easier for whoever can add the table entry. In haste, Richard Fobes On 8/4/2021 6:08 PM, robert bristow-johnson wrote: > i just got offa the phone with a Dr. Tideman. you guys might know him. could someone here, who is more qualified than me, put in a new line into this table at Wikipedia: > > https://en.wikipedia.org/wiki/Comparison_of_electoral_systems#Compliance_of_selected_single-winner_methods > > for BTR-STV ? https://electowiki.org/wiki/Bottom-Two-Runoff_IRV > > I know that BTR is Condorcet-compliant (which means that it cannot be LNH) and that, strictly, it's not precinct summable (if there was a cycle, you don't know from the summable defeat data who wins). But I am not qualified to get the facts and authoritatively evaluate each criterion and say "yea" or "nay" to it. > > geez, i can't pay you, but i can beg. > > -- > > r b-j rbj@audioimagination.com > > "Imagination is more important than knowledge." > > . > . > . > ---- > Election-Methods mailing list - see https://electorama.com/em for list info >

On 05.08.2021 03:08, robert bristow-johnson wrote: > i just got offa the phone with a Dr. Tideman. you guys might know him. could someone here, who is more qualified than me, put in a new line into this table at Wikipedia: > > https://en.wikipedia.org/wiki/Comparison_of_electoral_systems#Compliance_of_selected_single-winner_methods > > for BTR-STV ? https://electowiki.org/wiki/Bottom-Two-Runoff_IRV > > I know that BTR is Condorcet-compliant (which means that it cannot be LNH) and that, strictly, it's not precinct summable (if there was a cycle, you don't know from the summable defeat data who wins). But I am not qualified to get the facts and authoritatively evaluate each criterion and say "yea" or "nay" to it. > > geez, i can't pay you, but i can beg. This is what I know: Every monotonicity property IRV fails, BTR-STV/BTR-IRV also fails. Majority, Condorcet: pass (obviously; all implied by Condorcet) Smith, Mutual majority, majority loser, Condorcet loser: pass (Smith implies the rest) Clone independence: fail (crowding: https://www.rangevoting.org/BtrIrv.html) IIA: fail Reversal symmetry: fail (because IRV fails it) Consistency: fail (winner consistency incompatible with Condorcet, and no Condorcet method but Kemeny passes social order consistency) Participation, favorite betrayal: fail (incompatible with Condorcet) Later-no-help, later-no-harm: fail (ditto) Polynomial runtime: O(n^2) Summable: O(n!) Resolvability (Woodall's version): pass if the elimination count breaks ties by second preference (then third, fourth, etc), otherwise I don't know. Also (not mentioned on the list): Plurality: pass Mono-add-top: fail (incompatible with having both Smith and Plurality) These I'm not 100% certain about: LIIA: Pretty sure this is a fail, though I could be wrong. ISDA: Not sure, but I would expect fail. So all we need to do is to find a LIIA failure and an ISDA failure. Anyone got such failures? I'm kinda thinking I should make a simple Python program "How Your Method Sucks" that finds criterion failures. I kid :-) About the title, at least. It *would* be nice to just throw a method at some program and get "definitely fails these". -km

thanks for doing this. i might email you directly if i need help decoding it. > On 08/05/2021 10:32 AM Kristofer Munsterhjelm <km_elmet@t-online.de> wrote: > > > On 05.08.2021 03:08, robert bristow-johnson wrote: > > i just got offa the phone with a Dr. Tideman. you guys might know him. could someone here, who is more qualified than me, put in a new line into this table at Wikipedia: > > > > https://en.wikipedia.org/wiki/Comparison_of_electoral_systems#Compliance_of_selected_single-winner_methods > > > > for BTR-STV ? https://electowiki.org/wiki/Bottom-Two-Runoff_IRV > > > > I know that BTR is Condorcet-compliant (which means that it cannot be LNH) and that, strictly, it's not precinct summable (if there was a cycle, you don't know from the summable defeat data who wins). But I am not qualified to get the facts and authoritatively evaluate each criterion and say "yea" or "nay" to it. > > > > geez, i can't pay you, but i can beg. > > This is what I know: > > Every monotonicity property IRV fails, BTR-STV/BTR-IRV also fails. > Majority, Condorcet: pass (obviously; all implied by Condorcet) > Smith, Mutual majority, majority loser, Condorcet loser: pass (Smith > implies the rest) > Clone independence: fail (crowding: https://www.rangevoting.org/BtrIrv.html) > IIA: fail > Reversal symmetry: fail (because IRV fails it) > Consistency: fail (winner consistency incompatible with Condorcet, and > no Condorcet method but Kemeny passes social order consistency) > Participation, favorite betrayal: fail (incompatible with Condorcet) > Later-no-help, later-no-harm: fail (ditto) > Polynomial runtime: O(n^2) > Summable: O(n!) > Resolvability (Woodall's version): pass if the elimination count breaks > ties by second preference (then third, fourth, etc), otherwise I don't know. > > Also (not mentioned on the list): > Plurality: pass > Mono-add-top: fail (incompatible with having both Smith and Plurality) > > These I'm not 100% certain about: > > LIIA: Pretty sure this is a fail, though I could be wrong. > ISDA: Not sure, but I would expect fail. > > So all we need to do is to find a LIIA failure and an ISDA failure. > Anyone got such failures? > > I'm kinda thinking I should make a simple Python program "How Your > Method Sucks" that finds criterion failures. > > I kid :-) About the title, at least. It *would* be nice to just throw a > method at some program and get "definitely fails these". > > -km -- r b-j . _ . _ . _ . _ rbj@audioimagination.com "Imagination is more important than knowledge." . . .