The 24-Hour Effect
Breaking down the numbers behind this season’s back-to-backs
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There’s nothing particularly new about the concept of playing college basketball games on consecutive days. Most early-season tournaments and conference tournaments are set up that way, and some teams have even done that in the conference regular season before (looking at you, Ivy League!)
There’s one big difference this year, however. In order to limit travel and risk of coronavirus exposure, many leagues have scheduled back-to-backs at the same location against the same opponent. This model has given coaches a unique opportunity to play chess — making adjustments in the hours following a game and implementing them 24 hours later. It’s also given us an excellent set of data to analyze. So let’s dive in and answer some of the biggest questions about the effects of this season’s back-to-backs. Note that only same-venue back-to-backs between the same two teams are included here, for a total of 406.
How do day one winners do on day two?
They say it’s hard to beat the same team three times in one season. Is it hard to beat the same team twice in two days? Not especially, it would seem. Day one winners have won again on day two about two-thirds of the time, posting a record of 272-134 on day two and winning by an average of 13.7 points.
However, if your team just lost the opener of a back-to-back, there’s good news in the numbers: Nearly 70% of teams that lost on day one (280 out of 406) improved their margin on day two. Your team may not win tomorrow, but it is likely to at least make things closer.
Do road teams fare better on day two?
Without fans — or at least with limited attendance — the biggest remaining advantages for home teams are lack of travel, familiarity with the venue (rims, shooting backdrops, etc), and for some, altitude. It stands to reason that these advantages would diminish on the second day of a back-to-back series when the road team has already played a game in the same location approximately 24 hours prior and had time to acclimate.
Well, if road teams are supposed to be better adjusted by day two, then someone forgot to tell them that. Visitors are actually two games better than .500 on day one at 203-201 (two back-to-back series have been played at a neutral site) but are just 184-220 on day two. Point differential for road teams gets slightly worse as well, going from -0.2 to -1.1. We’ll take a closer look at how much home court advantage still exists this season in an upcoming article, but whatever hindrances there are left for road teams certainly don’t go away on the second day of back-to-backs.
Do teams play tired on day two?
Another common theme among broadcasters and coaches alike this season is fatigue. It makes sense that 80 minutes of basketball in 24 hours would lead to some tired legs. There are a couple of ways we can measure how tired teams are on day two of back-to-backs: pace and fouls. Tired teams play slower, and tired defenders foul more.
Both of these measures do give credence to the idea that players are more fatigued after playing the previous day. Average pace slows down by over a full possession on day two, dropping from 70.6 to 69.4. Despite that slower pace, total fouls per game increase from 33.7 to 35.0. (Hoop Vision’s Jordan Sperber found that these trends exist on the men’s side as well.) The cliché about depth being more important in a tournament setting may be more than just a cliché.
Are there other statistical differences?
We’ve looked at pace and fouls, but do any other numbers change significantly from day one to day two? For the most part, other stats remain the same. Rebounding, turnovers, two-point and three-point shooting, shot blocking, and steals stay pretty much constant across both days. But there is one other stat that changes: free throw shooting.
Teams improve their average free throw percentage by almost two percentage points from day one to day two — from 68.4% to 70.2%. This increase is seen for both home teams and road teams, and it’s also present for both winners and losers.
It’s tough to know why this is, but one theory lies in who is taking the shots. Because there are more fouls on day two, there are likely more bonus free throws. That means there are more free throws taken by players who were fouled on the floor. Since guards spend more time handling the ball, they are more likely to be fouled while not in the act of shooting. Guards on the whole shoot free throws better than bigs, so more free throws attempted by guards should mean more free throws made overall.
How big are the biggest turnarounds?
Perhaps the most fun analysis that back-to-backs have given us is an illustration of how truly random the game of basketball can be. Sure, there are big turnarounds every year when teams play each other twice. But it’s often hard to know whether those turnarounds were driven by random chance or an actual basketball factor. If a team gets blown out by 30 and then comes back and wins the rematch two months later, it could be random, but it also could be based on a number of other things — a player injured in one game but healthy in the other, a midseason coaching adjustment that led to a team playing better later in the year, having to go on the road in game one and getting home court advantage in game two.
With a few small exceptions, both games of a back-to-back are basically played under the same circumstances, which means huge turnarounds can almost entirely be chalked up to the sheer unpredictable nature of the sport. Then again, that may be doing a disservice to the ability of some coaches to make impressively quick adjustments. Let’s take a look at which teams have changed their fortunes the most from day one to day two. (Extra shout out to Appalachian State, who beat Georgia Southern the day after losing by 31!)
With mere days until conference tournaments get underway, we’re approaching the time of year when teams usually start to play on two (or even three or four) straight days. Will some teams and players be more prepared for it after doing it for much of the regular season? It’s hard to say, but this season has given us some new insight into how teams perform on short rest. Still, let’s just hope we never have another season like this one.
All data is from Her Hoop Stats and is updated through games played on February 21.
Thanks for reading the Her Hoop Stats Newsletter. If you like our work, be sure to check out our stats site, our podcast, and our social media accounts on Twitter, Facebook, and Instagram. You can also buy Her Hoop Stats gear, such as laptop stickers, mugs, and shirts!
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