====================================================================== SOURCE FILE: bv2151_97hbpw_ranked_robin.yaml TABULATED FILE: bv2151_97hbpw_ranked_robin_tabulated.txt ====================================================================== election_title: "Felsenthal Ex.4 after two no-shows — Ranked Robin: unmoved, still Beth" scenario_description: |- Race 2 of 3 in the No-Show-paradox pair, part 2 of 2 (BV2151, bvid 97hbpw; BV-confirmed). Source: Dan S. Felsenthal (2010), Appendix A2, Example 4 — see bv2151_97hbpw_irv.yaml for the setup. The same 9 ranked ballots counted by Ranked Robin (Copeland): Beth still wins both head-to-heads (Andy 6–3, Carl 5–4) — the Condorcet winner, elected directly. Ranked Robin elects Beth with 11 voters (BV2150) and with 9: in this pair, showing up never hurt the Andy voters under a pairwise count. (Condorcet methods are not participation-proof in general — Moulin's theorem — but this electorate doesn't trigger it.) Live results: https://bettervoting.com/97hbpw/results bv_test_id: BV2151 bv_election_id: 97hbpw bv_results_url: https://bettervoting.com/97hbpw/results paradoxes: [no-show] voting_method: RankedRobin num_winners: 1 ballots: |- 2:Andy>Beth>Carl 3:Beth>Carl>Andy 1:Carl>Andy>Beth 3:Carl>Beth>Andy expected_winners: - Beth # file: bv2151_97hbpw_ranked_robin.yaml ====================================================================== TABULATION RESULTS ====================================================================== --- Ranked Robin (RCV-RR / Copeland) Method (single winner) --- Tabulating 9 ballots (ranked ballots). Ballots: 2 × Andy > Beth > Carl 3 × Beth > Carl > Andy 1 × Carl > Andy > Beth 3 × Carl > Beth > Andy Round-Robin — every pair, head-to-head (For – Against): Beth beats Andy 6 – 3 Carl beats Andy 7 – 2 Beth beats Carl 5 – 4 --- Pairwise (Round-Robin) Matrix --- Head-to-head / pairwise comparison — the Ranked Robin tally Legend: For - Equal Support - Against (row vs column) | Andy | Beth | Carl | -------------------------------------------- Andy > | --- |3 - 0 - 6 |2 - 0 - 7 | Beth > | 6 - 0 - 3 | --- |5 - 0 - 4 | Carl > | 7 - 0 - 2 |4 - 0 - 5 | --- | Win–loss record — Copeland score = wins + ½·ties (highest score wins; ties broken by total margin, then lot order): # Candidate W–L–T Copeland Margin Beats 1 Beth 2–0–0 2 +4 Carl, Andy 2 Carl 1–1–0 1 +4 Andy 3 Andy 0–2–0 0 -8 — Winner — Ranked Robin (RCV-RR): Beth beats every opponent head-to-head — the Condorcet winner. --- 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 3): Beth Outside (2): Andy, Carl One member ⇒ Beth is the Condorcet winner, beating every rival head-to-head. Ranked Robin (RCV-RR) winner Beth is INSIDE the Smith set. ✓ Guaranteed: Ranked Robin (Copeland) is Smith-efficient — every member of the set outscores every outsider, so the top of the win–loss table is always inside the set, however the tie among them is then broken. More: 07_Concepts/topics/smith_set.md