BV2132 — Pet poll (RCV-IRV): center squeeze elects Fish¶

Generated from bv2132_ykjjhy_pet_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: Fish

▶ Live on BetterVoting: vote · results ↗ (election ykjjhy · test BV2132).

Scenario¶

One of the four races in the BV2132 "Pet poll" (BetterVoting election ykjjhy). This is the RCV-IRV race (ranked ballots, instant runoff). Cat is the Condorcet winner (beats Dog 13-9 and Fish 15-7), but has the fewest first choices (6), so IRV eliminates Cat FIRST; its ballots transfer to Fish, which then beats Dog 13-9. So IRV elects Fish — a textbook center squeeze: the compromise candidate is dropped before the final round. Same electorate as the Plurality race (Dog) and the Approval/STAR races (Cat). BV also elects Fish. Live results: https://bettervoting.com/ykjjhy/results

Ballots¶

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

9:Dog>Cat>Fish
7:Fish>Cat>Dog
6:Cat>Fish>Dog

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) ---
  BV2132 — Pet poll (RCV-IRV): center squeeze elects Fish
 Tabulating 22 ballots (ranked ballots).

ROUND 1
Candidate      Votes  Status
-----------  -------  --------
Dog                9  Hopeful
Fish               7  Hopeful
Cat                6  Rejected

FINAL RESULT
Candidate      Votes  Status
-----------  -------  --------
Fish              13  Elected
Dog                9  Rejected
Cat                0  Rejected


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

--- Transfers and inactive ballots (what the round tables leave out) ---
The tables above give each candidate's round total but not where a
transferred vote came FROM, nor how many ballots stopped counting.
Both are recomputed from the ballots, using the eliminations the
count above actually made.

ROUND 1 — 22 of 22 ballots still active; majority = 12
   Cat eliminated with 6:
      → Fish                      6

FINAL ROUND — 22 of 22 ballots still active; majority = 12
   Fish                     13  (59.1% of the still-active)  ← elected
   Dog                       9  (40.9% of the still-active)
   Never exhausted, never transferred:
      9 ballots held by Dog carried a lower ranking that was never read
      (the count stopped here, so those preferences did nothing).

Inactive ballots at the final round: 0 of 22 (0.0%).
   Fish's 13 is a majority of the 22 still active AND of all 22 cast (59.1%).

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 3): Cat
   Outside (2):        Dog, Fish
   One member ⇒ Cat is the Condorcet winner, beating every rival head-to-head.
   RCV-IRV winner Fish is OUTSIDE the Smith set. ✗
      Every member of the set (Cat) beats Fish head-to-head, yet
      RCV-IRV elected Fish 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/pet_poll_four_methods/cases/bv2132_ykjjhy_pet_irv.yaml

BV2132 — Pet poll (RCV-IRV): center squeeze elects Fish¶

Scenario¶

Ballots¶

What the engine says¶

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

See also¶