====================================================================== SOURCE FILE: bv2282_hf3ckp_brams_irv.yaml TABULATED FILE: bv2282_hf3ckp_brams_irv_tabulated.txt ====================================================================== election_title: "Brams 1982 — twenty-one voters, and the Condorcet winner goes out second" scenario_description: |- A 21-voter, 4-candidate profile from Stephen J. Brams, "The AMS Nomination Procedure Is Vulnerable to 'Truncation of Preferences'," Notices of the American Mathematical Society 29:2 (February 1982), 136-138 — reproduced via rangevoting.org, which cites it as an RCV-IRV example. Counted by Hare: B leads on 7 first choices, F (3) is eliminated and sends 3 to N, then G is eliminated on 6 and sends all 6 to B, who wins 13 of 21. But G beats B head-to-head 14-7, and beats N 13-8 and F 18-3 — G is the Condorcet winner, and is eliminated one round before the finish. It is the smallest example in this folder: 21 ballots, checkable on paper in about a minute, which is what makes it the one to hand someone who does not want to take a 303-voter profile on trust. PROVENANCE, STATED CAREFULLY. The profile is Brams's; the RCV-IRV reading is rangevoting.org's. Brams's paper is about vulnerability to PREFERENCE TRUNCATION — voters ranking only some candidates — which is a different argument from the Condorcet failure shown here, and we could not confirm from the abstract whether the AMS procedure of the day was Hare specifically. So: cite Brams for the ballots, and cite this file for what Hare does with them. Do not write "Brams showed that IRV..." — he did not, in this paper. Candidate labels B, G, N, F are Brams's own and are kept for traceability to the source, which is why they are neither alphabetical nor in reading order. BV-CONFIRMED. Race 1 of live election hf3ckp (Test ID BV2282) is these 21 ballots counted by BetterVoting's own IRV tabulator, and it elects B, matching this file exactly; race 2 is the same ballots under Ranked Robin and elects G. tieBreakType 'none' in both. Frozen export: bv2282_hf3ckp_bv_export.json. Live on BetterVoting: https://bettervoting.com/hf3ckp Live results: https://bettervoting.com/hf3ckp/results bv_test_id: BV2282 bv_election_id: hf3ckp bv_results_url: https://bettervoting.com/hf3ckp/results voting_method: RCV_IRV num_winners: 1 # Source profile: Brams (1982), via https://rangevoting.org/rangeVirv.html # section 12. Claim-checked in this folder's README.md. ballots: |- 7:B>G>N>F 6:G>B>N>F 5:N>G>B>F 3:F>N>G>B expected_winners: - B # file: bv2282_hf3ckp_brams_irv.yaml ====================================================================== TABULATION RESULTS ====================================================================== --- RCV / Instant-Runoff Voting (single winner) --- Brams 1982 — twenty-one voters, and the Condorcet winner goes out second Tabulating 21 ballots (ranked ballots). ROUND 1 Candidate Votes Status ----------- ------- -------- B 7 Hopeful G 6 Hopeful N 5 Hopeful F 3 Rejected ROUND 2 Candidate Votes Status ----------- ------- -------- N 8 Hopeful B 7 Hopeful G 6 Rejected F 0 Rejected FINAL RESULT Candidate Votes Status ----------- ------- -------- B 13 Elected N 8 Rejected G 0 Rejected F 0 Rejected Winner(s) — RCV / Instant-Runoff Voting (single winner) B --- Smith Set (the generalized Condorcet winner) --- The smallest group whose every member beats every candidate outside it — the honest answer to "who is even in contention?". Smith set (1 of 4): G Outside (3): B, N, F One member ⇒ G is the Condorcet winner, beating every rival head-to-head. RCV-IRV winner B is OUTSIDE the Smith set. ✗ Every member of the set (G) beats B head-to-head, yet RCV-IRV elected B anyway. RCV-IRV is not Smith-efficient (nor Condorcet-efficient) — this is the shape a center squeeze leaves behind. More: 07_Concepts/topics/smith_set.md