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Show HN: 2026 Midterms Tracker blends polls and Kalshi/Poymarket odds

10 points - today at 6:19 PM

Source
  • shoo

    today at 10:58 PM

    PressAudit's Pr(D win house) = 0.80 is a lot lower than the forecasts from The Economist (0.96) & FiftyPlusOne (0.99)

    PressAudit's Pr(D win senate) = 0.63 is in the ballpark with forecasts from The Economist (0.58) & FiftyPlusOne (0.73)

    Here's what PressAudit's midterms forecast page says about methodology:

    > PressAudit probabilities blend recent polls with Polymarket and Kalshi odds, giving polls more weight as more surveys become available. Chamber-control odds come from 10,000 simulations that account for shared national and state-level shifts. These are experimental estimates, not guarantees; the simulation assumptions have not been historically calibrated.

    Hmm. In contrast, FiftyPlusOne's forecasting model doesn't use prediction markets as inputs:

    > Other forecasters are increasingly using prediction markets as signals in their forecasting systems. We do not [...] There is a poisonous logical circularity in using prediction markets to update a statistical model when the statistical model is itself being factored into the prediction market. Because of these limitations, our opinion is that if you’re going to inject prediction market data into your forecasting model, you should at least let users view a version that doesn’t rely on such data.

    [1] https://www.economist.com/interactive/2026/us-midterms/predi...

    [2] https://fiftyplusone.news/

    [3] https://blog.fiftyplusone.news/p/2026-forecast-methodology

    • ls612

      today at 10:51 PM

      This is very similar to https://electionbettingodds.com/ which has been doing this for decades at this point.

      • RunningDroid

        today at 10:23 PM

        s/Poymarket/Polymarket/

          • SLHamlet

            today at 10:32 PM

            lol yes