[Don Dollars]

I was wondering if anyone has any information on the impact that OVERTIMES has in NBA Over/Under wagering.

How much is this factored into a line? How much of a compensation needs to be used to adjust appropriately?

Almost all UNDERS that are played are going to lose if their is an overtime. How big of an impact will this have? How much does it strengthen OVER plays? Any insight would be GREATLY APPRECIATED!

[The HG]

Overs caused by OT is not an insignificant thing in the NBA. According to my records, last year in the regular season, overs were 598-614, 49.3%. However, 44 of those overs were caused by OT, meaning at the end of regulation the total was an under, but after the OT periods the total was an over. That's more than 7% of all the overs for the entire season. Without the OTs, overs would have been 554-658, or 45.7% league-wide.

However, I have never seen anything that indicates that certain NBA games are more or less likely to go into OT (as opposed to baseball, where there are distributions that indicate that certain games are more or less likely to have an exact tie game at the important number for baseball totals, 4-4). Other than the fact that games with lower spreads are more likely to go into OT than games with higher spreads, of course, because those games are more likely to be closer in general.

But I assume that the spread and resulting likelihood of OT is factored into the line. In other words, each added point in a spread has a certain value putting downward pressure on the total, exclusively due to OT. Oddsmakers are certainly aware of that and factor it in to their totals.

[Don Dollars]

Overs caused by OT is not an insignificant thing in the NBA. According to my records, last year in the regular season, overs were 598-614, 49.3%. However, 44 of those overs were caused by OT, meaning at the end of regulation the total was an under, but after the OT periods the total was an over. That's more than 7% of all the overs for the entire season. Without the OTs, overs would have been 554-658, or 45.7% league-wide.

However, I have never seen anything that indicates that certain NBA games are more or less likely to go into OT (as opposed to baseball, where there are distributions that indicate that certain games are more or less likely to have an exact tie game at the important number for baseball totals, 4-4). Other than the fact that games with lower spreads are more likely to go into OT than games with higher spreads, of course, because those games are more likely to be closer in general.

But I assume that the spread and resulting likelihood of OT is factored into the line. In other words, each added point in a spread has a certain value putting downward pressure on the total, exclusively due to OT. I assume oddsmakers are aware of that and factor it in, although I'm certainly not sure.

Excellent post. Thank you!

[Jay Edgar]

I haven't handicapped totals, but you could probably take a pass at a "risk of OT" factor to apply in handicapping them.

The way I'd think of it, you need to take a stab at quantifying the risk to your under bet that more than 4 qtrs will be played (which probably translates to an over at least 95% of the time.) What's the risk in this particular game? Well in an average game (whatever that is), it'd be the overall likelihood of overtime in all NBA games. As Ganchrow notes, nobody's sure which games are more likely to go OT, but you probably can't go wrong in assuming that the closer the game is to pick 'em, the more likely you'll get OT. So if the average spread is 4.5, and if 3% of all games go OT (I'm making these numbers up) and if you only make a bet normally when you think you have a 57% likelihood of winning, then in an average spread game (4.5) you should only bet under if you think you have a 58.5% likelihood of the 4-qtr total being under, and you should require up to 60% confidence in the 4-qtr under as you get closer to pick 'em. Conversely, you would need to be someting less than 58.5% confidence in games with bigger favorites -- maybe almost all the way back down to the 57% standard in projected blowouts.

On the flip side, you could make over bets when you had 55.5% confidence about the 4 qtr over in an average game, going up to 57% in a tight spread game and down to as low as 54% in a projected blowout.

But of course very few people factor OTs into their betting of overs. That just feels wrong. But it's really no different than worrying about the overtime creating a bad beat for your under play.