Ossipoff's 303 — the first-round LEADER is eliminated¶

Generated from bv2281_qycpbx_ossipoff_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 qycpbx · test BV2281).

Scenario¶

A constructed 5-candidate, 303-voter profile published on rangevoting.org (Warren D. Smith's site, section 12, credited to Mike Ossipoff). Reproduced here exactly as given, because it is a sharper example than the one it is usually filed under.

The textbook center squeeze eliminates a Condorcet winner who holds FEW first choices — that is the whole mechanism, and it lets a defender answer "well, nobody actually wanted them first." This profile removes that answer.

C holds 100 of 303 first choices — the LARGEST first-choice bloc in the field, ahead of D (53), B (51), A (50) and E (49). C is also the Condorcet winner, and not narrowly: C beats A 202-101, B 202-101, D 201-102 and E 201-102 — roughly two to one against every rival. RCV-IRV eliminates C in round 3 and elects D.

The elimination order is what does it. E goes first (49), and every one of those ballots reads E>D, so D climbs to 102. A goes next (50), and those ballots read A>B, so B climbs to 101. C, who led the entire count on 100, is now the lowest of the three left and is cut — at which point C's 100 ballots read C>D and hand D the election 202-101.

Read this fairly. It is CONSTRUCTED, not a real election, so it proves that RCV-IRV CAN do this, not that it usually does — Condorcet failures showed up in 2 of 182 US RCV elections studied. Its one-dimensional layout (A-B-C-D-E left to right, C in the middle) is the standard spatial model rather than a transcript of any electorate. And the source page is score-voting advocacy with a polemical tone; the PROFILE is arithmetic and reproduces exactly, which is why it is here and the rhetoric is not.

Bare letters are deliberate: this is an abstract published illustration, and A-E are the source's own labels.

BV-CONFIRMED. Race 1 of live election qycpbx (Test ID BV2281) is these 303 ballots counted by BetterVoting's own IRV tabulator, and it elects D, matching this file exactly; race 2 is the same ballots under Ranked Robin and elects C. tieBreakType 'none' in both. Frozen export: bv2281_qycpbx_bv_export.json.

Live on BetterVoting: https://bettervoting.com/qycpbx Live results: https://bettervoting.com/qycpbx/results

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¶

Round-by-round Sankey diagram: each candidate's votes as a band, and where the votes of an eliminated candidate transferred to.

Where the votes went. Band thickness is votes; a band leaving an eliminated candidate lands on whoever that ballot ranked next, or on inactive if it ranked nobody who was left.

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

--- RCV / Instant-Runoff Voting (single winner) ---
  Ossipoff's 303 — the first-round LEADER is eliminated
 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/rangevoting_irv_examples/cases/bv2281_qycpbx_ossipoff_irv.yaml

Ossipoff's 303 — the first-round LEADER is eliminated¶

Scenario¶

Ballots¶

What the engine says¶

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

See also¶