IRV buries the centrist — Ossipoff's 303-voter one-dimensional example (BV2158)¶

Generated from bv2158_gr72hd_ossipoff_centrist_irv.yaml — do not edit by hand. Regenerate: python STARVote_LH_tabulation_engine/tools_adam/scripts/build_yaml_pages.py.

Method: RCV-IRV (Instant Runoff) · 1 seat · Expected winner: D

▶ Live on BetterVoting: vote · results ↗ (election gr72hd · test BV2158).

Scenario¶

Mike Ossipoff's 1-D example (via rangevoting.org). Candidate C is the centrist: C is the PLURALITY winner (100 first-choices, most of any) AND the Condorcet winner (beats every rival ~2:1). Yet RCV-IRV ELIMINATES C in round 3 and elects D. Sincere ballots; a realistic 'one-dimensional politics' taper. Ranked-ballot case (no scores invented). Approval/STAR/Condorcet/Ranked Robin would all elect C. Level 301. Source: https://www.rangevoting.org/rangeVirv.html (section 12). Live results: https://bettervoting.com/gr72hd/results (all races LH<->BV confirmed). Lesson: bv2158_gr72hd_ossipoff_centrist_irv.md Live on BetterVoting: https://bettervoting.com/gr72hd/results (BV-confirmed; STAR is race 1).

Ballots¶

Each row is one voter's ranking, most-preferred first (N: prefix = N identical ballots).

50:A>B>C>D>E
51:B>A>C>D>E
100:C>D>B>E>A
53:D>E>C>B>A
49:E>D>C>B>A

What the engine says¶

The count, step by step — the rounds and how the winner is reached:

--- RCV / Instant-Runoff Voting (single winner) ---
 Tabulating 303 ballots (ranked ballots).

ROUND 1
Candidate      Votes  Status
-----------  -------  --------
C                100  Hopeful
D                 53  Hopeful
B                 51  Hopeful
A                 50  Hopeful
E                 49  Rejected

ROUND 2
Candidate      Votes  Status
-----------  -------  --------
D                102  Hopeful
C                100  Hopeful
B                 51  Hopeful
A                 50  Rejected
E                  0  Rejected

ROUND 3
Candidate      Votes  Status
-----------  -------  --------
D                102  Hopeful
B                101  Hopeful
C                100  Rejected
A                  0  Rejected
E                  0  Rejected

FINAL RESULT
Candidate      Votes  Status
-----------  -------  --------
D                202  Elected
B                101  Rejected
C                  0  Rejected
A                  0  Rejected
E                  0  Rejected


Winner(s) — RCV / Instant-Runoff Voting (single winner)
  D

Full audit — preference matrix, Condorcet, and score distribution¶

--- 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 5): C
   Outside (4):        A, B, D, E
   One member ⇒ C is the Condorcet winner, beating every rival head-to-head.
   RCV-IRV winner D is OUTSIDE the Smith set. ✗
      Every member of the set (C) beats D head-to-head, yet
      RCV-IRV elected D 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

Everything in one file: the _tabulated mirror (regenerated on every run; every analysis forced on).

Run it yourself:

python STARVote_LH_tabulation_engine/starvote_larry_hastings.py method_comparisons/paradoxes_and_whoops/cases/bv2158_gr72hd_ossipoff_centrist_irv.yaml

IRV buries the centrist — Ossipoff's 303-voter one-dimensional example (BV2158)¶

Scenario¶

Ballots¶

What the engine says¶

Full audit — preference matrix, Condorcet, and score distribution¶

See also¶