538's presidential forecast this year differs quite a bit from Nate Silver's forecast (paywalled), and much of the media/pundit consensus of the race. Some have pointed out things that they view as internal inconsistencies, and broadly the top-line as of writing this having Biden as a very, very slight favorite is surprising (at least to me) given recent polling.

Is this based on modeling differences, only resolvable by evaluation of long term performance, or is this a straightforward bug? 538 went against the grain and was vindicated in 2016 (but that was back when they had Nate Silver and his model) - is this time different?

Fine Print:

• Resolves based on statements from 538 or ABC News (from anyone who credibly speaks for them, on any platform)

• "Presidential Forecast" here refers only to the topline prediction percentage.

• "Bug" is subjective - I reserve the right to make a judgment call. I will not bet on this market.

  • Some examples of bugs:

    • Math error in the code that results in incorrect output

    • Unintentional misconfiguration of parameters

    • Data input cleaning/parsing issues

  • Some examples that are not bugs

    • Intentional, but in retrospect overly/underly aggressive parameter choices (weighting of fundamentals, time decay, etc)