Most player props come with one main line: 24.5 points, over -110, under -110. Many books also offer alternate lines: the same stat at other thresholds, each with its own price. Over 19.5 points might be -250, over 29.5 points +260.
Alt lines can look like a menu of bets. They're really a set of probabilities, one per rung, and reading them that way is what makes them useful.
The ladder
An alt-line ladder for one player might look like this:
| Line | Over price | Break-even |
|---|---|---|
| 19.5 | -250 | 71.4% |
| 22.5 | -150 | 60.0% |
| 24.5 | -110 | 52.4% |
| 27.5 | +160 | 38.5% |
| 29.5 | +260 | 27.8% |
The lower the line, the more likely the over, so the shorter the price. Each price converts to a break-even win rate (the odds converter does this for any price). Read down the right-hand column and you have the book's view of the whole distribution: roughly 71% he scores 20 or more, about 28% he scores 30 or more.
Books build ladders from one estimate
A book doesn't price each rung from scratch. It starts with a projection for the player and a view of how spread out his outcomes are, then prices every rung off that. That's useful to know for two reasons.
First, the rungs should be consistent with each other. If the main line and the ladder disagree (say the main line implies a coin flip at 24.5 but the alt ladder implies 58% over 24.5), one of them is stale, and one side is better than it should be.
Second, the far rungs carry more margin. Books often price the long shots (over 34.5, over 39.5) with a bigger cut than the main line, because few people check them against the rest of the ladder.
Pick'em ladders
Pick'em apps don't use prices, so their alt lines work differently. Instead of a longer or shorter price, a lower line pays a smaller multiplier and a higher line pays a larger one. The same idea applies: compare each rung against what sportsbooks imply for that threshold. If a sportsbook ladder says over 19.5 is a 71% shot and an app pays as if it were 60%, that rung is the better bet.
Where the value tends to be
- Across books, not within one. One book's ladder is internally consistent most of the time. The gaps appear when you line two books' ladders up at the same threshold.
- After news. When a teammate is ruled out, books update main lines quickly. Alt ladders sometimes lag, especially the far rungs.
- Between lines. If one book's over 22.5 and another's under 24.5 can both be bet, there's a window where both win. That's a middle, and alt lines are where most middles come from.
Things to watch for
Long shots are tempting because the payout is big, but a +400 rung only needs to be wrong a little to be a bad bet. Check its break-even (20% at +400) against the rest of the ladder before you take it.
And remember that the rungs are linked. Betting over 22.5 and over 27.5 on the same player isn't two independent bets. If he has a bad night, both lose together.
Betravon shows every book's alt-line ladder side by side for each prop, so you can see where one book's rung is out of line with the others. Start with today's NBA player props or NFL player props.