House of Pain

Which markets did least poorly on the hardest call of the cycle?

While most in the legacy forecasting set are still polishing off their humble pie, prediction markets by and large saw Trump’s victory coming nearly a month out.

Where they stumbled a bit was in foreseeing that Republicans would keep their majority in the House of Representatives.

In the six weeks leading up to the election, the favorite flipped several times, with the GOP never getting above the mid-50s. In the end, they basically heralded a coin flip (not a terrible prediction, considering the final tally will once again be a closely divided chamber).

But clearly the markets covered themselves in less glory with their Congressional prognositcation than their Presidential, which outperformed (nearly) all pro forecasters.

So who did best and worst in what turned out to be the most challenging 2024 outcome to handicap?

To find the answer, we looked at minute-by-minute pricing of the GOP majority contract on

Polymarket

, Betfair, Smarkets, Metaculus, Kalshi and our own Super Model aggregate, from the moment Kalshi began trading on October 2, through election night at midnight (when it was still not a done deal).

We compared three metrics:

• Percent of the time the price favored the correct outcome (above $0.50)

• Average price over those five weeks

• Average price over the final 24 hours

For each metric, the higher score the better. Weighing all three equally, we present you our official House majority forecast rankings:

1. Polymarket

2. Super Model

3. Kalshi

4. Betfair

5. Smarkets

6. Metaculus

We’ll use these and other predictive metrics collected this cycle to refine our weightings of the various markets for our aggregates going forward.