HOW PROBABILITY PRICING WORKS
On a binary prediction market, the price IS the implied probability. A $0.65 YES contract means the market is pricing 65% odds. Once you internalize that, everything else clicks.
Every binary prediction market settles at $1 if YES wins and $0 if NO wins. So the current trading price of YES, between $0 and $1, directly reflects the market's collective probability estimate. If YES trades at $0.30, the market thinks the event has a 30% chance of happening.
Your edge isn't predicting the future — it's spotting markets where your probability estimate diverges meaningfully from the price. If you think YES is really 50% likely and it's trading at $0.30, you have a 20-point edge. Buy YES at $0.30; if you're right, expected value is $0.50 - $0.30 = $0.20 per contract.
The math of expected value is unforgiving. A 5-point edge (you think 50%, market says 45%) is real but small — you'll lose more often than you win on individual trades, and only repetition over many independent markets shows the edge. A 20-point edge is rare and means you should size up. Anything above 30 points should make you suspicious — either you're missing something or the market is illiquid.
Where edges actually come from: domain expertise (you work in the industry the market is about), faster information processing (you read primary sources before they hit news), or behavioral mispricings (markets systematically over- or under-react to recent events). Generic 'gut feel' is not an edge.
Takeaways
- →Price = implied probability. $0.65 means 65%.
- →Edge = your probability minus the market's, not your conviction.
- →5-point edges are real; 30-point 'edges' usually mean you're missing something.
- →Domain expertise and faster information processing are the real sources of edge.