RCV-IRV — a basic ranked-ballot example (3 candidates)¶

Generated from RCV_ballot_example.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: A

Scenario¶

A first ranked-ballot count: 100 voters, three candidates, weighted rows like "40:A>C>B". A leads with 40 first choices but no majority; C (25) is eliminated, C's ballots transfer to A, and A wins 65-35. Use it to learn the round-by-round report before the pathology cases (center_squeeze, monotonicity, summability in method_comparisons/) show what elimination order can do.

Ballots¶

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

40:A>C>B
35:B>C>A
25:C>A>B

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) ---
  RCV-IRV — a basic ranked-ballot example (3 candidates)
 Tabulating 100 ballots (ranked ballots).

ROUND 1
Candidate      Votes  Status
-----------  -------  --------
A                 40  Hopeful
B                 35  Hopeful
C                 25  Rejected

FINAL RESULT
Candidate      Votes  Status
-----------  -------  --------
A                 65  Elected
B                 35  Rejected
C                  0  Rejected


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

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): C
   Outside (2):        A, B
   One member ⇒ C is the Condorcet winner, beating every rival head-to-head.
   RCV-IRV winner A is OUTSIDE the Smith set. ✗
      Every member of the set (C) beats A head-to-head, yet
      RCV-IRV elected A 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 06_Other/RCV_IRV/cases/RCV_ballot_example.yaml

RCV-IRV — a basic ranked-ballot example (3 candidates)¶

Scenario¶

Ballots¶

What the engine says¶

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

See also¶