BV2105 — Favorite ice cream (Bloc STAR, 2 seats): a partial ballot mis-filed as an abstention¶

Generated from bv2105_r4dqvd_ice_cream_bloc.yaml — do not edit by hand. Regenerate: python STARVote_LH_tabulation_engine/tools_adam/scripts/build_yaml_pages.py.

Method: Bloc STAR (multi-winner, majoritarian) · 2 seats · Expected winners: Chocolate, Strawberry

▶ Live on BetterVoting: vote · results ↗ (election r4dqvd · test BV2105).

Scenario¶

The LH reference for BetterVoting test BV2105 (election r4dqvd, "Favorite ice cream (Bloc STAR) - without end date"). Bloc STAR, 3 flavors, 2 seats, 4 ballots. Live results: https://bettervoting.com/r4dqvd/results Frozen raw export: bv2105_r4dqvd_ice_cream_bloc_bv_export.json.

The four ballots:

Vanilla,Chocolate,Strawberry 5,5,5 an all-5s ballot (loves everything) -,-,- fully blank — a TRUE abstention 1,-,- Vanilla=1, the rest blank — a REAL (partial) vote 2,5,4 a full ballot

Winners (both engines): Chocolate, Strawberry. Chocolate takes seat 1; seat 2 is a Vanilla/Strawberry runoff TIE (1-1) broken by score — Strawberry 9 > Vanilla 8 — so BetterVoting's tieBreakType "score" and LH agree exactly.

THE REGRESSION (counting, not tabulation). BetterVoting's summaryData reports nTallyVotes = 2 and nAbstentions = 2, i.e. it counts only the two FULL ballots and files BOTH the blank ballot AND the partial "1,-,-" ballot as abstentions. The LH engine counts 4 ballots with just 1 abstention (only the fully-blank row); the "1,-,-" ballot is a cast vote — LH's Score Distribution shows Vanilla with a real "1" and a total of 8. You can see BV dropped it: its per-candidate "score" is the average over 2 ballots (Vanilla (5+2)/2 = 3, not (5+2+1)/3), so the partial ballot never entered the tally.

Same winners here (the dropped ballot only helped Vanilla, the seat-2 loser), so this is a REPORTING/counting regression rather than a wrong result — but a discarded cast ballot can flip closer elections. It is the opposite-direction sibling of BV15 / bettervoting#740: #740 DROPS abstentions from the displayed turnout; BV2105 mis-classifies a real partial ballot AS an abstention.

CITATION CORRECTION (2026-08-04). This file used to credit the miscount to bettervoting#1056 and call it fixed. Both were wrong. #1056 is a DIFFERENT defect on the same demo election — a 401 blocking JSON/CSV download and Race Details, introduced by the Editable Ballots work (#979) and correctly closed via #1058. The two share only the BV2105 test-document name. The counting defect described above is a separate bug, filed 2026-08-04 as bettervoting#1478.

The behavior is unchanged a year on. The re-check ran on 2026-08-04: the same four ballots, cast fresh through the live API so today's tabulator counts them, come back nTallyVotes 2 / nAbstentions 2 — identical to the numbers frozen here. That re-run is its own case, BV2105-r2 (election w3vvff, bv2105r2_w3vvff_ice_cream_recheck.yaml), which also explains why re-fetching THIS election could not have answered the question: r4dqvd is closed, so its stored ElectionResult may just be the 2025 tally.

Likely root: bettervoting#884's rule that an all-equal ballot is an abstention. A ballot bearing ONE mark is trivially all-equal, so it falls through the same test — which would make this intended behavior rather than a coding slip. The counter-argument is that a voter who scores Vanilla 1 and leaves the rest blank HAS expressed a preference, because BV's own tally treats those blanks as 0.

This file is therefore the 2025 BASELINE, and this LH reference pins the correct count (4 ballots, 1 abstention, 3 tallied, Vanilla total 8).

Ballots¶

Row 1 = candidate names; each later row is one voter's 0–5 scores (a N × prefix = N identical ballots).

Markers on these ballots: - blank · ~ race abstention · & candidate abstention · ? spoiled · % spoiled+reissued — all tabulate as 0 (reported honestly).

Vanilla,Chocolate,Strawberry
5,5,5
-,-,-
1,-,-
2,5,4

What the engine says¶

The count, step by step — the rounds and how the winner is reached:

[Divergence from STAR]
  STAR                   = Chocolate
  Choose-One (Plurality) = Vanilla   (differs from STAR)
  RCV-IRV                = Vanilla   (differs from STAR)
  Note: 1 of 4 ballots (25%) had equal non-zero scores, so their ranks were
        decided by candidate priority order. The RCV-IRV result may be an
        artifact of score-to-rank tie-breaking rather than a deep
        difference.
  Note: Ranked Robin (RCV-RR) agrees with STAR, so RCV-IRV is the lone
        outlier — the classic center-squeeze signature.
  Full round-by-round reports (generated for review):
  RCV-IRV rounds: cases_tabulated/bv2105_r4dqvd_ice_cream_bloc_RCV-IRV_tabulated.txt

--- Bloc STAR Voting Method (2 winners) ---

[Bloc STAR]
 Tabulating 4 ballots to fill 2 seats. Note: 1 of 4 ballots is marked as an abstention.
Vanilla,Chocolate,Strawberry
      5,        5,         5
      -,        -,         -
      1,        -,         -
      2,        5,         4
  ('-' = left blank / abstained; '0' = scored zero — both count as 0 stars.)

[Bloc STAR: Round 1: Scoring Round]
 The two highest-scoring candidates advance to the next round.
   Chocolate     -- 10 -- First place
   Strawberry    --  9 -- Second place
   Vanilla       --  8
 Chocolate and Strawberry advance.

[Bloc STAR: Round 1: Automatic Runoff Round]
 The candidate preferred in the most head-to-head matchups wins.
   Chocolate     -- 1 -- First place
   Strawberry    -- 0
   Equal Support -- 3
 Chocolate wins.
   Runoff math:
     4  ballots cast
   − 3  Equal Support (no preference between the two finalists)
     ─
     1  voters with a preference  (majority = 1)
           Chocolate 1 (100%)  ·  Strawberry 0 (0%)

──────────────────────────────────────────────────

[Bloc STAR: Round 2: Scoring Round]
 The two highest-scoring candidates advance to the next round.
   Strawberry    -- 9 -- First place
   Vanilla       -- 8 -- Second place
 Strawberry and Vanilla advance.

[Bloc STAR: Round 2: Automatic Runoff Round]
 The candidate preferred in the most head-to-head matchups wins.
   Strawberry    -- 1 -- Tied for first place
   Vanilla       -- 1 -- Tied for first place
   Equal Support -- 2
 There's a two-way tie for first.

[Bloc STAR: Round 2: Automatic Runoff Round: First tiebreaker]
 The highest-scoring candidate wins.
   Strawberry    -- 9 -- First place
   Vanilla       -- 8
 Strawberry wins.

[Bloc STAR: Winners — Bloc STAR Voting Method (2 winners)]
 Chocolate
 Strawberry

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

--- Preference Matrix ---
Head-to-head / pairwise comparison
Legend: For - Equal Support - Against
        Informational only — not part of the 2-winner count below,
        so no Top-2 finalists are marked.
                   |     Vanilla    |   Chocolate   |   Strawberry  |
---------------------------------------------------------------------
         Vanilla > |      ---       |  1 - 2 - 1    |  1 - 2 - 1    |
       Chocolate > |   1 - 2 - 1    |     ---       |  1 - 3 - 0    |
      Strawberry > |   1 - 2 - 1    |  0 - 3 - 1    |     ---       |

[Condorcet Winner]
  No strict Condorcet winner; unbeaten candidates: Vanilla, Chocolate (pairwise ties)

[Condorcet Loser]
  No strict Condorcet loser; jointly weak Condorcet losers: Vanilla, Strawberry (winless — pairwise ties) — Vanilla elected by Choose-One (Plurality)!

[Score Distribution] (how many ballots gave each star rating)
                 Score
Candidate   5  4  3  2  1  0  Abs  | Total  Avg all  Avg rated
Vanilla     1  0  0  1  1  0    1  |     8      2.0        2.7
Chocolate   2  0  0  0  0  0    2  |    10      2.5        5.0
Strawberry  1  1  0  0  0  0    2  |     9      2.3        4.5
  Avg all   = Total / all ballots — a blank counts as 0, so this is the Total the Scoring Round ranks on, per ballot.
  Avg rated = Total / the ballots that scored this candidate (Abs excluded) — support among voters who had an opinion.

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 02_STAR_Bloc/02_Examples/cases/bv2105_r4dqvd_ice_cream_bloc.yaml

BV2105 — Favorite ice cream (Bloc STAR, 2 seats): a partial ballot mis-filed as an abstention¶

Scenario¶

Ballots¶

What the engine says¶

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

See also¶