Favorite betrayal (RCV-IRV) — HONEST: Left voters rank their favorite first, and their WORST wins¶

Generated from bv2227_3xgkck_honest_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: Right

▶ Live on BetterVoting: vote · results ↗ (election 3xgkck · test BV2227).

Scenario¶

The plainest form of the favorite-betrayal incentive, the one RCV voters keep asking about ("is it smart to rank my favorite second?"). Three candidates on a spectrum: Left, Center, Right. 34 voters. The 12 Left voters vote honestly — Left > Center > Right. But Center, everyone's second choice and the Condorcet winner, has the FEWEST first-choices (9) and is eliminated first; Center's ballots split, and RIGHT wins the final 18-16. The Left voters' sincere ballots elected their LEAST-favorite candidate. See the companion fb_irv_betray (2 of those Left voters rank Center first and Center wins) and fb_star_honest (STAR/Ranked Robin elect Center from these same honest preferences — no betrayal needed). Concept: favorite_betrayal_voting_301.md.

Ballots¶

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

12:Left>Center>Right
5:Center>Right>Left
4:Center>Left>Right
13:Right>Center>Left

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) ---
  Favorite betrayal (RCV-IRV) — HONEST: Left voters rank their favorite first, and their WORST wins
 Tabulating 34 ballots (ranked ballots).

ROUND 1
Candidate      Votes  Status
-----------  -------  --------
Right             13  Hopeful
Left              12  Hopeful
Center             9  Rejected

FINAL RESULT
Candidate      Votes  Status
-----------  -------  --------
Right             18  Elected
Left              16  Rejected
Center             0  Rejected


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

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): Center
   Outside (2):        Left, Right
   One member ⇒ Center is the Condorcet winner, beating every rival head-to-head.
   RCV-IRV winner Right is OUTSIDE the Smith set. ✗
      Every member of the set (Center) beats Right head-to-head, yet
      RCV-IRV elected Right 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/favorite_betrayal_irv/cases/bv2227_3xgkck_honest_irv.yaml

Favorite betrayal (RCV-IRV) — HONEST: Left voters rank their favorite first, and their WORST wins¶

Scenario¶

Ballots¶

What the engine says¶

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

See also¶