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BV750 — Bloc STAR tie-breaking, every ballot identical · issue #1052 family

Method: Bloc STAR (multi-winner, majoritarian) · 2 seats · Expected winners: c, a · full count →

The extreme flat case: a 2-seat Bloc STAR election where all three ballots are 5,5,5. Nothing separates anyone, so the lot decides both seats — and BetterVoting drops every ballot as an abstention (nTallyVotes: 0, the "no ballots have been cast" bug). LH and BV both elect c, a (via the lot), but LH counts all three ballots.

Reference files: bv750_tie_breaking_bloc.yaml (expected_winners: [c, a]) · frozen export bv750_tie_breaking_bloc_bv_export.json (BV 3yr2qd). Backs sheet row BV750.

The election

Bloc STAR, 3 candidates, 2 seats, 3 ballots — all identical:

a,b,c
5,5,5
5,5,5
5,5,5

Every candidate totals 15; every voter is indifferent among all three.

View 1 — BetterVoting

Elected c, a, tieBreakType: "random", perm = [c, a, b] (the draw picks the two finalists and both winners). But its summaryData reports nAbstentions: 3, nTallyVotes: 0 — BV classified all three all-equal ballots as abstentions and tallied nothing, so it shows the "no ballots" state (#1052 / #1407). An all-equal ballot is a real vote of no preference, not an abstention.

View 2 — the LH report (all three ballots counted)

LH counts every ballot; each candidate really totals 15, and the tie is genuine at every rung, so the lot decides both seats:

Abridged for the lesson — not verbatim engine output
--- Bloc STAR Voting Method (2 winners) ---
 Tabulating 3 ballots.

[Score Distribution]
   5  4  3  2  1  0  | Total
a  3  0  0  0  0  0  |   15
b  3  0  0  0  0  0  |   15
c  3  0  0  0  0  0  |   15

Round 1: Scoring Round
   a 15 ; b 15 ; c 15                     ← three-way tie
Round 1: First tiebreaker (pairwise)
   a 0 ; b 0 ; c 0 ; Equal Support 3      ← pairwise tied
Round 1: Second tiebreaker (most 5s)
   a 3 ; b 3 ; c 3                        ← five-star tied
[Tiebreaker: Lot Number Priority]  Resolved: ['c', 'a']   (lot [c, a, b])
[Lot-decided tie — rare]
Round 1: Automatic Runoff (c vs a) — tied at every rung → lot → c

Round 2: Scoring Round
   a 15 ; b 15 — a and b advance
Round 2: Automatic Runoff (a vs b) — tied → lot → a

Winners — Bloc STAR Voting Method (2 winners)
 c
 a
Full audit copy: _main_tabulated/bv750_tie_breaking_bloc_tabulated.txt.

Two findings

  1. Every ballot dropped (#1052/#1407). nTallyVotes: 0 — BV treats all-equal ballots as abstentions and tallies none, so it reports "no ballots cast" even though three voters participated. LH keeps them as Equal Support.
  2. Random tie-break → non-reproducible (cf. #1063 / #1417). Identical ballots separate nobody, so both seats are a coin toss; lot_numbers: [c, a, b] pins BV's draw. The winners can't be affected by the dropped ballots — only by the lot order.