Chicken / Burr dilemma — Approval, honest: A and B tie 60-60 (the trap)¶

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

Method: Approval Voting · 1 seat · Expected winner: A

Scenario¶

The same electorate as chicken_star, under APPROVAL voting with honest ballots: the 60 A/B voters approve both allies (utility above the midpoint), the 40 C voters approve C. Result: A 60, B 60 — an exact tie (broken here only by candidate priority order), with C safely defeated at 40. This is the chicken / Burr dilemma: the honest cooperative play leaves A and B in a dead heat, so each side is tempted to bullet-vote (approve only its favorite) to win outright — a slippery slope that, if both sides defect far enough, lets the majority-opposed C slip through. The A/B tie is the whole point (as with Jefferson & Burr in 1800), so this case is LH/pref_voting-verified rather than frozen from a random BetterVoting tie-break. STAR removes the slope entirely — see chicken_star.yaml. Concept: ../../07_Concepts/topics/strategic_pathologies.md.

Ballots¶

Row 1 = candidate names; each later row is one voter's approvals (1 = approve, 0/blank = not approved).

Count:A,B,C
35:1,1,0   # approve A and B
25:1,1,0   # approve A and B
40:0,0,1   # approve C

What the engine says¶

Full report from the _tabulated mirror (regenerated on every run; every analysis forced on):

--- Approval Voting (single winner) ---
 Tabulating 100 ballots (any non-zero score = approval).

Ballots:
   columns = A, B, C      (1 = approve; 0 = not approved)
    60 × 1,1,0
    40 × 0,0,1

   A -- 60 (60%) -- Elected
   B -- 60 (60%)
   C -- 40 (40%)
  Note: A, B each have 60 approvals and tie for the last 1 seat.
        Candidate priority order (A > B) broke the tie: A elected, B not elected.

[Approval Distribution] (how many candidates each ballot approved)
   160 approvals across 100 ballots — average 1.6 of 3 (range 1–2).
     approved 1: 40 ballots
     approved 2: 60 ballots

[Co-Approval Matrix]
 Of the voters who approved the ROW candidate, the % who ALSO approved the COLUMN candidate.
      |   A    |   B    |   C    |
   -------------------------------
   A  |   --   |  100%  |   0%   |
   B  |  100%  |   --   |   0%   |
   C  |   0%   |   0%   |   --   |

Winner — Approval Voting (single winner)
  A

Run it yourself:

python STARVote_LH_tabulation_engine/starvote_larry_hastings.py method_comparisons/chicken_dilemma/cases/chicken_approval.yaml

Chicken / Burr dilemma — Approval, honest: A and B tie 60-60 (the trap)¶

Scenario¶

Ballots¶

What the engine says¶

See also¶