by Warren Smith, Oct 2022.
As of 2022 many towns in Utah run elections with "instant runoff voting," (IRV) employing rank-ordering ballots. And in some cases Utah wants to elect two, not one, seats. Utah's procedure for doing that (which also is what Australia would usually do during 1919-1949 when electing 2 seats) might be called the "1+1" method:
That differs from the more direct 2-winner IRV method proposed by Seattle WA (in 8 Nov.2022's "ballot proposition 1B"). Seattle's approach was simply to eliminate the candidate top-ranked by the fewest voters, then redo that over and over (usual IRV process) until only two candidates remain un-eliminated – Seattle's two winners.
These two procedures always agree for at least one of their 2 winners. But they can disagree about the second winner. The question is how often such "1+1≠2" disagreements happen.
Here are all the Utah bi-IRV elections during 2019-2021 for which we were able to determine the "1+1" and "2" winners.
| # | Election | 1+1 winners | 2 winners |
|---|---|---|---|
| 1 | Draper council at large, seats 1&2, 2021 | TASHA LOWERY + MIKE GREEN | LOWERY & HUBERT HUH |
| 2 | Payson City Council seats 1&2, 2019 | DOUG WELTON + BRIAN HULET | WELTON & LINDA CARTER |
| 3 | Genola council 4yr seats 1&2, 2021 | HALE ROBISON + GRANT LUNDBERG | ROBISON & LUNDBERG |
| 4 | Lehi council seats 1&2, 2021 | CHRIS CONDIE + PAUL HANCOCK | CONDIE & MICHELLE MILES |
| 5 | Springville council 4yr seats 1&2, 2021 | MICHAEL SNELSON + CRAIG JENSEN | SNELSON & CRAIG CONOVER |
| 6 | Vineyard council seats 1&2, 2021 | MARDI SIFUENTES + AMBER RASMUSSEN | SIFUENTES & RASMUSSEN |
| 7 | Woodland Hills council seats 1&2, 2021 | JANET LUNT + DOREL B. KYNASTON | LUNT & TOBY M. HARDING |
| 8 | Moab council seats 1&2, 2021 | JASON TAYLOR + JOSIE KOVASH | TAYLOR & LUKE WOJCIECHOWSKI |
| 9 | City of Bluffdale council at large, seats 1&2, 2021 | WENDY W. ASTON + TRACI CROCKETT | ASTON & CROCKETT |
| 10 | River Heights City council seats 1&2, 2021 | JANET H. MATHEWS + TYSON GLOVER | MATHEWS & NANCY HUNTLY |
| 11 | Heber City council seats 1&2, 2021 | D.SCOTT PHILLIPS + YVONNE M. BARNEY | PHILLIPS & BARNEY |
| 12 | Newton town council seats 1&2, 2021 | JAKE CHRISTIANSEN + BRETT PETERSEN | CHRISTIANSEN & GORDON A. ANDERSEN |
| 13 | Nibley City council seats 1&2, 2021 | KATHRYN A. BEUS + NORMAN LARSEN | BEUS & LARSEN |
The "1+1≠2" paradox occurs in 8 of these 13 cases. This demonstrates that, 62% of the time, something is wrong with either 1-winner IRV or 2-winner (Seattle style) IRV voting – or both.