Methodology
No black box. Here is exactly how Bankroll Guardian turns raw sportsbook prices into fair odds, expected value, and the one number that actually tracks a long-term edge — plus how we decide a pattern in your history is real.
1. Implied probability & the vig
Every price implies a win probability. A -110 line implies 110 ÷ (110 + 100) = 52.4%. Add up both sides of a -110 / -110 market and you get 104.8%, not 100%. That extra 4.8% is the vig(or hold) — the book's built-in margin, and the reason both sides can't be fair at once.
2. Fair (no-vig) odds
To find the true price, we strip the vig out. We take each side's implied probability and divide by their sum, so the two sides add back to a clean 100%. Two -110 lines de-vig to 50% / 50% — a fair price of +100each. That's the number a bet would need to be a coin flip in your favor.
3. Market consensus — the “true” odds
No single book is gospel. We de-vig every book pricing a market, then take the medianfair probability across all of them. The median shrugs off one book with a stale or outlier line, giving a robust estimate of the market's true probability. That consensus is what we price value and grade CLV against — not any one sportsbook's opinion.
4. Expected value (the green value cards)
A price is +EVwhen it beats the consensus fair probability. If the market's true price is +100 (50%) and a book is offering +105, your expected value is (2.05 × 0.50) − 1 = +2.5%— you're getting paid more than the risk is worth. On the Live Odds board that surfaces as a +X% EV value tag. Consistently taking +EV prices is, mathematically, the whole game.
5. Closing Line Value (CLV) — the honest scoreboard
Whether a single bet won or lost is mostly luck; whether you beat the closing lineis skill. CLV compares the price you got to the market's consensus price at kickoff. Beat the close over and over and you have a real edge, even through a cold streak. We capture closing lines automatically near kickoff and grade every eligible bet, so your average CLV and beat-the-close rate are measured for you — not self-reported. It's the metric sharp bettors trust above win rate, and the reason we built the product around it.
6. How we validate edges & leaks
The Edge & Leak finder scans your settled bets for slices — a sport, a bet type, a book, a price range — that run clearly positive or negative. The danger with any pattern-finder is mistaking a hot or cold streak for a real trend. So we don't just report the pattern; we test it.
We split the slice's bets in half by date and check whether the same edge (or leak) shows up in both halves independently. If it does, it's marked ✓ Holds out-of-sample— it held on data it wasn't discovered on. If there isn't enough history to split, or it only appears in one half, it's flagged Provisional: a hint worth watching, not a verdict. Nothing here is a betting recommendation — it's a mirror of your own results.
What we don't do
We don't sell picks, predictions, or “locks,” and we never take a cut of your bets or a sportsbook affiliate fee — so nothing here is nudging you to wager more. Bankroll Guardian is a bet-tracking & analytics tool, not a sportsbook. Everything above is informational, not betting or financial advice. 19+/21+ where applicable — if gambling stops being fun, take a break, and reach out for help.
See it in action
Run the numbers yourself with the free calculators, or start tracking to get your own CLV and edge report.
Bankroll Guardian is operated by 1545194 B.C. LTD. — a bet-tracking & analytics tool, not a sportsbook. We never accept wagers or hold funds.