How has Play Differed in the Bubble?

By Andrew Lawlor

The NBA has been back for a couple weeks now, and we have gotten somewhat used to seeing the bubble games. But the quality of play is slightly different from before. With the seeding games officially over and the playoffs about to begin, let’s take a look at some statistics from inside the bubble.

Scoring Has Increased

There was talk going into the bubble that the gyms had great sightlines for shooting. There are no fans, so there is a constant backdrop behind each shot, and the arenas are smaller than typical NBA arenas. This also helps with players’ depth perception, as bigger arenas have led to worse shooting in NCAA games. Devin Booker told The Ringer that it was a “hooper’s gym.” Indeed, scoring has risen inside the bubble; teams are averaging 115.7 points per game since the restart compared to 111.4 before. The average offensive rating has risen as well, from 111.2 to 113.0. The rise in offense remains true even in games with bubble teams only. This means the reason for the rise is not due to filtering out bad teams.

Before the ShutdownBefore the Shutdown (Bubble Teams Only)After the Restart
Games19421032176
Points Per Game111.4111.9115.7
Offensive Rating111.2111.4113.0
3PT%35.7%35.9%36.3%
3-Point Rate38.2%38.5%40.5%
FG%46.0%46.0%46.4%
FT%77.1%77.8%79.1%
eFG%52.8%52.7%53.7%
Fouls Per Game20.620.722.9
FTA Per Game22.922.825.4
Table by Andrew Lawlor

It may indeed be that it is easier to shoot in the bubble. Field goal percentage, three-point percentage, and free throw percentage have all risen. Teams are also taking slightly more of their shots from three-point range and at the rim.

Teams are taking more three-pointers and shots at the rim

An interesting note is that free throw shooting has improved, but the improvement has come almost entirely on the second shot. Seth Partnow of The Athletic found that, as of August 8, that players are shooting 73.9% on the first foul shot and 82.2% on the second shot. Before the shutdown, the split was 74.8% on the first shot and 79.1% on the second. The increased split could be noise, but it could be because players need to calm themselves before shooting. The weird environment without fans could contribute to this. Some coaches have noticed this phenomenon and started to “ice” foul shooters by calling timeouts in between free throws.

Referees are Calling More Fouls

Another reason for the increase in offense is an increase in fouls being called. There have been about 2.5 more fouls called per game, and teams are taking a little less than three free throws per game more than they were before the shutdown.

Perhaps this is because teams are still working out the kinks. Everybody had a long layoff before the restart, and teams did commit more fouls at the beginning of the season as well before settling in. If this is the cause for the increase, then we will probably see fewer fouls called as we get into the playoffs.

It could also be because there is no crowd noise. Referees are more likely to hear players getting hit or jawing at each other. If this is the cause, the increase in fouls may continue.

Chart by Andrew Lawlor

Turnovers are Slightly Up

In the first quarter of the Rockets-Lakers game last week, Danny Green caught the ball on the sideline, and began to drive. But Green had stepped out of bounds while starting his move. The play was dead on arrival. A few possessions later, James Harden did the same thing on the other end. Players seem to be struggling to get used to staying in bounds on the new courts without fans right there.

It is hard to tell if players are truly stepping out of bounds more, since I do not have a good data set for specific turnover types. But turnovers overall have increased slightly. Turnovers per game for bubble teams have increased from 13.5 to 14.3 since the restart. This is not a huge increase, but it’s not nothing either.

The Games are Close

Before the ShutdownBefore the Shutdown (Bubble Teams Only)After the Restart
Games97151688
% in Overtime6.3%5.4%9.1%
% One-possession15.0%15.9%15.9%
Avg. Margin of Victory11.510.910.3

The games inside the bubble have been tight. A significantly higher portion have gone to overtime than before the shutdown, though a similar amount have been one-possession games. The reason for the increased number of overtime games could simply be due to the limited amount of games. But it has been great for fans so far.

In addition to being closer, games have also been longer. The average game in the bubble is nearly ten real-time minutes longer than the average game from before the bubble, according to Basketball Reference. The increase in overtimes has certainly been a cause. Increased fouls have also probably had something to do with it.

Home Court Advantage is Still a Factor

Designated home teams during the shutdown have very few of the advantages that typical home teams have. They do not have a travel advantage, as all games are played at the same site now. There is no crowd. They did not spend the night before the game in their own beds. Yet “home” teams in the bubble have so far maintained a home court advantage. They are winning at a similar rate to home teams before the bubble, although they do have a smaller average margin of victory.

Before the ShutdownBefore the Shutdown (Bubble Teams Only)After the Restart
Games97151688
Home Team Winning %55.1%57.6%55.6%
Avg. Home Margin of Victory2.22.71.6
This Andrew Lawlor guy is pretty smart, huh?

 “Home” teams in bubble games have had the same average overall net rating (2.0) as “away” teams. So the observed home court advantage is not happening because stronger teams have overwhelmingly been designated “home.”

Inside the bubble, there are advantages given to home teams. The court is decked out in the iconography of the home team, and the virtual fans in the stands all come from the home team. The sounds piped into the stadium benefit the home team. It is possible that these advantages are really helping home teams. But it is too early to know for sure, and it likely is not as big of an advantage as a real home game.

Site Owner’s Note: Andrew has been absolutely crushing it. I will continue to push for you to follow him on Twitter. Do it!

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