Betting: Will fans at NBA games impact point spreads?

Preston Johnson is joined by the Action Network's Matt Moore and Justin Phan to discuss how to bet when large crowds come back to NBA games.

Video Transcript

MATT MOORE: We got a question here from James Hezra. How much would a full capacity crowd sway the lines in the playoffs? #nbabetstream. You can ask questions to us using #nbabetstream on Twitter. I actually did a deep dive on this and talked to bookmaker's for a piece I did on Action Network about a week ago, and the responses were really interesting.

Most of the books I talked to said that they were going to watch it and see how the teams' performances against the spread changed as more and more fans were added back to the arenas. Right now, you have a lot of differing amounts. It's not just the attendance like it usually is.

You have some arenas that are at 10%, 12% capacity. Some are going to 30%. Some are expecting 75% when they get closer to the playoffs. So all of these factors I think go into it.

I do think, though, that there's going to be an adjustment period I think from teams. We're seeing this trend very steadily. Teams that are used to playing in front of fans that have fans in their home arena are more comfortable on the road versus going from at home without fans to an arena that's more full. You're seeing kind of an impact. So I do kind of wonder if in the playoffs as things get really intense if we're going to see some of those swings happen with against the spread margins based off of the crowd. Justin, do you have thoughts on that?

JUSTIN PHAN: Yeah. I mean, just from a betting perspective, my plan is to kind of gradually smooth in and normalize my home away impact in terms of my model as we see arenas kind of scale back up and allow more fans to normal capacity. I'm curious as to your and Preston's point of view. For me, it's not any different in the playoffs than in seasons past. Do you kind of anticipate that being the case, or do you see it being a little bit different this time around?

MATT MOORE: Preston?

PRESTON JOHNSON: I'm going to say I skimmed your article, Matt. So I'll say I did spend a few minutes on it. The numbers were interesting, and you could probably relay that exact percentages better than I could. I know at the beginning of the year a lot of road teams are winning more frequently because I think the market was overvaluing home court advantage to some extent, but it's kind of caught up.

And then you had some interesting numbers on the Jazz and teams that have actually, as a whole, had some fans to this point in the season. I think it was like 133 and 128 against the spread, which, more or less, is 50-50. So it looks like the market was not recognizing that there were fans in a home court scenario in those 261 instances, right?

So I don't think there's going to be much of a difference as they had 5, or 10, or 15,000 more of the fans for a lot of these teams. And if there is, the market's going to account for it anyway. There's not going to be some secret hidden like, blindly betting home teams that have at least 15 or more fans that night. Like, I just don't envision it.

And in the end, look, the impact of home court exists. Fans are a very small part of it though. And it's such a small amount regardless that I think the rest and the actual spot as far as is it the fourth game in seven nights for the team that they're playing? And who's actually playing the back-to-backs and some of those other situations are going to be affecting a home court advantage more than the fans do regardless.

So in the end, I think the fans effecting a home court point spread-- I mean, like, if you want to say it's a full capacity's like a point and no capacity is 0, you shouldn't really be sweating or blindly betting something that is probably only a quarter to a half a point difference than the true price than the market's probably already accounting for anyway. So for me, it's I think a lot of kind of guesswork that's not necessary.

So I think that's my warning or telling people don't get too caught up in the fact that there's certain arenas that have more fans than others and that they're supposed to perform better. It's just not much of a difference in the end, in my opinion. And if there is one, the market's probably accounting for it any way.