Pathological Scenarios for the New York Mayoral Election

  • While the most likely outcome of the New York Mayoral election is an uncontroversial win for Eric Adams, especially as he leads first preference polling, and in practice many voters do not use ranking even when the option to do so is provided, some polling has suggested non-monotonic scenarios.

    Polling suggests that Eric Adams' worst matchup is against Kathryn Garcia. It tends to suggest that he would receive between 48% and 56% support. In contrast, he polls well against both Andrew Yang and Maya Wiley. No polls that have publicly released data about these pairwise matchups suggest he would do worse than 56% against Yang or 54% against Wiley.

    However, Garcia is no lock to make the final round. If Yang finishes 4th, Garcia and Wiley would be nearly tied for elimination. There is limited information on what will happen if Wiley finishes 4th, but what information exists suggests that Garcia would be eliminated in a final 3 against Adams and Yang.

    Here is an example of a poll that showed a nonmonotonic result:

    That said, I suspect that polls of the race may be overestimating voters' tendency to rank additional candidates just by explicitly asking about it. This reduces the chance of a paradox.

    Unfortunately, New York City does not appear to release the actual ballot data, so if a paradox does occur, we might not be able to catch it. Related:

    That said, they will release two preliminary reports that run through the IRV counting process before they have all of the ballots. This could be an effective demonstration of how chaotic the process can get if the absentee ballots change the ranking.

  • Update following the first preliminary results.

    Last night, the NYC Board of Elections released a preliminary IRV count. These results included several test ballots that should have been cleared from the system before counting the actual votes. This suggests incompetence on the part of the NYC Board of Elections, but it would be unfair to blame this on IRV. The revised results have just been released. All in all, they suggest that the polling before the race was generally accurate.

    The first preliminary count, which does not include absentee ballots, indicates that the final 3 candidates were Adams, Garcia, and Wiley. The chance that the absentee ballots change this is virtually zero.

    Garcia and Wiley are virtually tied for elimination in the round of 3. The current preliminary count has Garcia ahead of Wiley by 347 votes in this round (about 0.045% of the non-exhausted vote). In the final round, Adams leads Garcia by 14,755 votes (about 2.1% of the non-exhausted vote). (If you read my original post about this election, you might note that these results are not surprising.)

    With a bit more than 100,000 absentee ballots not considered in the computation, either outcome could conceivably change by the time all of the absentee votes are counted. Consequently, both the Garcia and Wiley campaign supporters believe that they could come back and win. But the Wiley supporters should be careful what they wish for. Wiley's head to head numbers against Adams were much worse than Garcia's in the pre-election polling. Unfortunately, because the NYC Board of Elections' implementation of IRV has been one of the least transparent in the US, we have no official data on the Wiley vs Adams pairwise matchup. If we did, I think it would clearly demonstrate that IRV still has a spoiler problem,since Wiley is far more likely to spoil a win for Garcia than become mayor herself.

  • No matter how this plays out this has been such bad press for IRV.

  • I'm surprised and sad that it seems really hard to get the actual round-by-round IRV results, and I haven't found anyone reporting them in a reasonable format. The best I've found is the official site, which has a separate page for each round and no calculations on shifts for each eliminated candidate:


    • Is there a better visualization anywhere?
    • Anywhere with a detailed comparison of results from each release of the data?
    • Any hope for CVRs so we can report this properly?

  • @nealmcb said in Pathological Scenarios for the New York Mayoral Election:

    Anywhere with a detailed comparison of results from each release of the data?

    Unfortunately it seems that the New York City board of elections has been removing the previous preliminary report with each release of a new one.

  • Thanks for posting this Psephomancy!
    I do hope someone here does a fully detailed data analysis and data visualization of the available data, and that they eventually release the full preference data and CVR.

    In retrospect, I also want to add that I'm impressed with the accuracy of your predictions of how this would all play out. I'm just surprised nobody predicted the ballot stuffing. That was just beyond...

Log in to reply