How we measure prediction markets.

1. Sourcing odds

We pull live midpoint prices from each platform's public API or order book. For binary YES/NO contracts we report the YES probability. For multi-outcome markets we report the leading outcome with its implied probability.

2. Normalizing across platforms

Polymarket prices in USDC (1.00 = certainty). Kalshi prices in USD cents (100¢ = certainty). Manifold uses mana but exposes a 0–100 probability. We normalize all three to a 0–100 implied probability after subtracting platform fees where applicable.

3. 24-hour change

Calculated as the difference between current implied probability and the volume-weighted average price 24 hours prior. Markets with less than $1,000 traded in the prior 24h are flagged as low-liquidity and excluded from "trending" rankings.

4. Liquidity score

A composite of (a) 24h notional volume, (b) order-book depth within ±5¢ of mid, and (c) number of unique counterparties. Used to rank comparable markets across platforms.

5. Platform comparisons

Fee tables are taken from each platform's published rate card and verified quarterly. Jurisdictional availability reflects each platform's stated terms of service plus our own VPN-free testing.

6. Corrections

We log material corrections at the bottom of affected pages and timestamp them. Email editorial@tomorrowalpha.com.