Definition
The natural swing in results around the long-run expectation caused by luck. A +EV bettor can lose over a span of weeks purely from variance; larger samples shrink its effect.
Related terms
- Sample Size — How many graded bets back a record. Small samples are mostly luck — trust records over hundreds of bets.
- Expected Value (EV) — The average profit or loss per unit staked if a bet were placed many times. A positive-EV (+EV) bet profits long-term even when single bets lose.