What is a Trap Over?
Short answer: A Trap Over is OpenSlate's name for an Over that looks cheap at DraftKings next to Pinnacle's no-vig price. A simple no-vig screener would call it value, but in OpenSlate's research Overs that look cheap this way have lost money, so they are listed apart instead of being treated as opportunities.
The idea
A no-vig screener compares DraftKings' price with Pinnacle's no-vig probability on the same line and calls the cheaper side "value". On Unders that comparison has been the basis of OpenSlate's research. On Overs it has not held up: in OpenSlate's research, Overs that DraftKings prices as less likely than Pinnacle does have lost money, both in last season's data and since launch.
Why would a cheap Over lose?
A plausible reason is how each book shades its lines. Recreational bettors favour Overs, so a retail book has room to price Overs less generously; an Over that still looks cheap may be one where the retail book knows something about minutes or role that the comparison misses. OpenSlate reports the measurement, not a theory it can prove.
How OpenSlate shows them
Trap Overs are listed apart from the main gap board, so they are never mistaken for opportunities. Pro members see the full list; the free tier shows a short sample.
Live figures appear here while today's lines are posted.
Related: what +EV means and why screens mislead, is Pinnacle sharper.
Isn't a cheap price always good?
Only if the reference price is right. The whole comparison rests on Pinnacle's no-vig probability being the better estimate. If that is less true for Overs than for Unders on player props, a cheap-looking Over is not cheap at all; it is a sign that the comparison is missing something. Measuring the result, rather than trusting the label, is the only way to know, and that is what the research did.
How to treat any "value" list
- Ask whether the list was checked on games played after it was built, not only on past data.
- Ask whether Overs and Unders were judged separately; they behave differently on props.
- Ask what price the result assumes; a price you could not get is not a result you could have had.
OpenSlate keeps the Trap Overs visible because hiding them would make the board look cleaner than the market is.
A note on the name
"Trap" describes how the line looks next to the reference price, not a claim about any single game. Any individual Trap Over can win. The name is a reminder that the comparison which works as a starting point on one side of the market has not held up on the other, so a cheap-looking Over deserves more scepticism, not less.
Related questions
- Are NBA rebound unders profitable?: an honest answer, and how to judge any claim that a market wins.
- How do I compare prop odds for free?: a step-by-step method and the free page that does it.
- What does closing line value tell me?: what beating the closing price shows, and what it cannot.
- What is the vig on DraftKings props?: how to measure the margin, with today's medians at both books.
Every answer on these pages is market data and education. OpenSlate does not publish free picks and does not tell you what to bet; it shows prices and measurements.
More: Removing the vig: how to turn two prices into a fair probability · Why Pinnacle is the reference price · Closing line value, explained · Why parlays cost more than the same bets straight · Why player prop lines move · Is DraftKings or Pinnacle sharper on NBA player props? · How do I calculate a no-vig price? · What is a +EV player prop? · Why do DraftKings and Pinnacle prop lines differ? · Are NBA rebound unders profitable? · How do I compare sportsbook prop odds for free? · What does closing line value tell me? · How often do prop lines move before tip-off? · What is the vig on DraftKings player props? · How do injury reports move NBA prop lines? · What is a market-maker sportsbook? · Is it better to bet the over or the under on player props? · Can you make money betting player props? · Can you bet at Pinnacle from the US? · What free tools help with player prop betting? · Does betting DraftKings when it disagrees with Pinnacle work? · What does over/under mean on a player prop? · How do sportsbooks set player prop lines? · What is a sharp bettor? · How do I convert American odds to implied probability? · What is a steam move in sports betting? · What are alternate lines on player props?
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