Methodology
Every number on Oddsloft comes from prices we archive ourselves and from official box scores. This page explains how each one is computed, so you can check it or cite it.
Prices
We record the prices of US-licensed sportsbooks for NBA and NFL games: moneylines, spreads, totals and over/under player props. Each book's line and both prices are kept from the first line to the start of the game. Betting exchanges and prediction markets are not sportsbooks and are left out of every table. Offshore books are never listed.
The consensus line
For every game, or every player and stat, the consensus line is the line most books closed on. On a tie we take the one nearest the books' median, so the consensus is always a line someone actually offered, never an average. The consensus opening line is built the same way from the opening lines.
Margin (vig, overround)
For each book and market we convert both closing prices to implied probabilities, add them up and subtract 100%. A market at -110 on both sides is 4.76%. The tables average this over every line a book posted. Player props are weighted by the number of lines in each stat. More on the math: implied probability and hold vs vig. Results: which sportsbook charges the most vig.
Grading player props
- Only finished games count. Each prop is graded against the consensus closing line and the official box score.
- A player who did not play leaves his line void. It is not a win or a loss for either side.
- The market's chance of the over is each book's two prices with the margin removed, the median across books, averaged per stat. Comparing it with the real over rate shows whether the price leaned the right way.
- A stat needs 200 graded lines and a book needs 30 lines before we show a number. Every table shows its sample.
Monthly editions
The monthly market report is a snapshot of the season to date at the end of each month. Once published, an edition does not change, which makes it safe to cite. Season pages such as the vig table update with every build.
Line moves
The weekly NFL line-move reports compare each game's consensus opening spread and total with the consensus close. After the games, we record how favorites did against the closing spread, how overs did against the closing total, and, for spreads that moved by a point or more, whether the result landed on the side the line moved toward, judged against the opening number. Pushes are counted separately.
Game projections
Our win chances come from statistical models that do not read betting prices, so they can be compared with the market.
- NBA: the strength of the players expected to play (individual impact ratings times expected minutes), season form measured by net rating, rest and back-to-backs, and home court. The injury report feeds who is available.
- NFL: an opponent-adjusted point-margin rating, the expected starting quarterback's efficiency per dropback, home field, rest after a bye or a short week, and time zones crossed.
A gap between a model and the market is not a betting signal. The market often prices news before any model does. See expected value and closing line value.
Updates and corrections
Pages with data are rebuilt every two hours and show the build time. Live odds pages read prices in your browser. If you find an error, write to [email protected] and we will fix it and note the change.