Validation sample: 6,776 markets

Original Vultax research: in an experimental test, a calibrated fair-value model beat raw Polymarket prices by ~9.6% on held-out Brier score. Where the favorite-longshot effect lives, what the model can honestly flag, and why it still isn't a trading edge. Prediction-market prices are good probability estimates on average — that is the standard result, and it held in our data. A fair-value model, honestly defined, answers one question: given where this market is priced, where did markets priced like it historically resolve?

- Brier improvement: ≈ +9.6%
- Where prices bend: Near 0 and 1

The observation window and population are stated in the study's method section.

Study: https://vultax.com/research/prediction-market-fair-value-calibration
Markdown: https://vultax.com/research/prediction-market-fair-value-calibration.md
Share card: https://vultax.com/og/article/research/prediction-market-fair-value-calibration
Live screen: https://app.vultax.com/analytics/markets

Vultax Research, We Tested Polymarket Prices Against 6,776 Resolved Markets. Here's Where They Bend., 2026-09-08, https://vultax.com/research/prediction-market-fair-value-calibration