Understanding randomness in sports betting
Why you can rarely know whether a single bet was the right decision — even after you see the outcome.
I study the statistics and decision theory of sports betting and prediction markets — as a scientist, not a tout. The public conversation is crowded with picks, affiliate rankings, and models marketed as edge. I work the empty seat: the independent voice that says whether a model, a market, or a claim is actually real, and how you would ever know.
My peer-reviewed work formalizes optimal decision-making under uncertainty in betting markets. The throughline: a billion dollars of real money usually out-forecasts a spreadsheet, the closing line is the only honest benchmark, and a single tournament can never validate a probability. I care about calibration and honesty about variance — not selling winners.
On Goldman Sachs’s World Cup prediction model, I told CNN it amounts to a “fun exercise” that sits further from reality than the prediction markets — because “the information going into the model is a tiny sliver of all the information in the possession of the millions of people who have bet into prediction markets.” Markets aren’t perfect either; they overreact to injuries and lean toward unlikely outcomes — and ultimately it’s impossible to know who was right.
The recurring ideas I bring to every model, market, and claim.
Aggregated, money-backed forecasts price in information no hand-built model can see. The bar isn’t picking the favorite — it’s beating the closing market price.
The closing line is the single number that actually predicts outcomes. Beating it consistently is the real evidence of edge; everything else is narrative.
A “26% to win the World Cup” number can never be validated — the tournament runs once. Many published forecasts are confident about quantities that are, in principle, uncheckable.
Sportsbook odds sum past 100%; near-zero-vig exchanges already read as probabilities. Comparing the two without removing the vig is the most common way analyses go wrong.
Aggregated independent forecasts converge to a robust estimate — but herding and favorite–longshot bias are real. The market is the best available estimate, not the truth.
A good forecaster is judged by calibration and honesty about variance, not by a winning week. You usually cannot know from one outcome whether a decision was right.
The peer-reviewed and open-source backbone behind the commentary.
A decision-theoretic framework for when a bet is objectively good or bad, independent of whether it wins — and what that implies for staking and evaluation under uncertainty.
A follow-up paper on the profit–bias identity in betting markets, and a quantile-regression model for NFL point spreads with full backtesting. Deep-dives will appear here as they’re ready.
Accessible essays on the statistics of betting. A newsletter is in the works.
Why you can rarely know whether a single bet was the right decision — even after you see the outcome.
Testing the “crossing key numbers” conventional wisdom on NFL teaser legs across multiple seasons.
I’m a standing resource for stories on betting models, prediction markets, and forecasting — the independent academic angle, not a tipster’s. Quick to respond, comfortable on deadline, and happy to translate the statistics into plain English.