How Accurate Is Polymarket? Data Analysis of 1000+ Markets

Calibration: What It Means

A prediction market is “well-calibrated” if outcomes priced at 70¢ happen approximately 70% of the time, outcomes at 30¢ happen 30% of the time, and so on. Perfect calibration means the market prices are the best available estimate of true probabilities.

Academic research and empirical analysis of Polymarket data shows that the platform is reasonably well-calibrated overall, but with systematic biases in specific categories. These biases are where traders make money.

A perfectly calibrated market would be untradeable — there would be no edge to exploit. The fact that Polymarket is generally accurate but imperfect is what creates opportunities for data-driven traders.

Where Polymarket Is Accurate

Polymarket performs best on:

• High-volume political markets — Presidential elections, major policy decisions. With $100M+ in volume, these markets aggregate enormous amounts of information efficiently.
• Events with clear information sets — Economic data releases (CPI, jobs reports) where the relevant inputs are well-known.
• Near-resolution markets — Markets within hours of resolution are highly accurate because most uncertainty has been resolved.

Where Polymarket Is Less Accurate

Systematic inaccuracies exist in several areas:

• Favorite-longshot bias — Heavy favorites (80¢+) are slightly overpriced, and longshots (20¢ and below) are slightly underpriced. Casual bettors overpay for “sure things” and underpay for upsets.
• Popular team bias in sports — Markets on Lakers, Warriors, Manchester City, and other popular teams tend to be overpriced on moneylines because casual bettors pile in based on name recognition rather than analysis.
• Draw probability in soccer — Draws are consistently underpriced across Polymarket soccer markets. The market underestimates draw frequency, creating a persistent edge for draw buyers in the right matchups.
• Late-breaking information — When news breaks (injury reports, lineup changes, policy leaks), the market takes 5–30 minutes to fully adjust. Smart money trades during this window, and following them via whale alerts lets you capture part of this inefficiency.
• Low-volume markets — Markets with under $10K in volume are often poorly priced because there aren’t enough informed traders to correct mispricings.

Smart Money vs Market Accuracy

An important distinction: the market price reflects the aggregate opinion of all traders. Smart money wallets are more accurate than the aggregate. This is proven by their realized PnL — wallets like DrPufferfish (91% WR, $3.7M profit) consistently estimate probabilities better than the market price suggests.

Edge Radar’s daily picks exploit this gap. The system identifies markets where smart money positioning suggests the true probability is significantly different from the current market price. Over 102 resolved picks, this approach has achieved 60.8% accuracy — meaningfully better than the market’s implied ~50%.

In other words: Polymarket is accurate enough to be useful as a forecasting tool, but inaccurate enough to be profitable for traders with better information — specifically, real-time data on what the most profitable wallets are doing.

Polymarket vs Other Forecasting Methods

Implications for Traders

The accuracy data tells us:

1. Don’t fight efficient markets — High-volume political markets are hard to beat. Focus your trading on sports and lower-volume markets where mispricings persist.
2. Exploit known biases — Favorite-longshot bias and popular-team bias are systematic. Building these into your strategy creates a structural edge.
3. Follow smart money, not the crowd — The aggregate market is decent. Smart money wallets are better. The gap between them is your profit.
4. Speed matters — Markets are most inaccurate during information shocks. Real-time whale alerts let you trade during these windows.
5. AI adds value on top of data — Pure AI is marginally better than the market (52–55%). AI combined with smart money data reaches 60.8%. The combination is key.