Issue #2: Go Your Own Way
Does the brand of basketball influence shooting percentages or attempts?
We hear it all the time: “Generics just aren’t the same!” Studies have shown that some patients respond differently between branded and generic medications. Is it psychological or physiological? One could ask the same question in many day-to-day situations. Is the 20 lb dumbbell in the gym actually lighter than the one at home or does it just feel that way?
During this season’s ongoing March Madness, the annual college basketball hoopla that makes amateur bracketologists of us all, we’ve heard small chatter from college basketball players about having to play with different brands of balls during away games. While the specifications of the balls are similar, the feel is often different between brands. If we’ve learned anything from college and professional athletes, it’s that they are creatures of habit. Sometimes the PSI needs to be just where athletes like it; just ask Tom Brady!
In this issue, we take a look at the athletic sponsors of colleges in the power 5 conferences and how specific brands of basketballs may impact shooting percentages.
The Chain of Brands
In sports, equipment uniformity is supposed to level the playing field. However, there are still many variables that can give certain teams and players advantages over each other. In college basketball, the game is played with the balls provided by the home team, which can be supplied by that team’s preferred manufacturer. While the general size, weight, and PSI of the balls must be uniform, each brand has a different feel and players tend to be fairly picky when it comes to the brand.
We conducted an analysis using data from the 2015-2016 college basketball regular season and conference tournaments  to examine what kind of impact the difference brands may have on shooting percentages and strategy.
Our analysis included colleges which are part of the “power 5” conferences which are the Atlantic Coast Conference (ACC), Big Ten (B1G), Big 12 Conference (Big-12), Pac-12 Conference (PAC-12), and the South Eastern Conference (SEC). For each of these schools, the brand of basketball used during home games as of January 2015  was used (Table 1).
Table 1 Included Schools and Brand of Basketballs
As shown above, the vast majority (67.19%) of schools use Nike-branded basketballs. The other prevalent brands include Wilson (17.19%), Under Armour (4.69%), and Adidas (4.69%).
Never Going Back There Again
Our analysis aimed to discover any differences in a team’s shooting percentages when changing from their normal brand of basketball to a different one in away games. To accomplish this, we compared the differences in shooting percentage between home and away games. The analysis included power 5 opponents only because data for basketball brands was only available for the power 5 schools.
Our base case analysis examined the differences in shooting percentage for Nike schools as they visited other schools. Table 2 presents the differences in mean shooting percentages for Nike schools segmented by the brand of basketball used.
Our baseline for this analysis is shown in the Nike column, which is the difference in mean shooting percentage for Nike schools between home opponents and away opponents when using Nike balls. It is important to understand that there is a baseline difference between home shooting percentage and away shooting percentage, even with the same brand of ball, because teams often shoot worse when away from their home campus.
Table 2 Nike Schools: Difference in Metrics Between Home and Away
The results of this analysis show that when Nike schools traveled to Adidas schools, the average field goal percentage (FG%), three-pointer percentage (3P%), and free throw percentage (FT%) were all much worse than if they were playing at a school using Nike balls. When Nike schools used Wilson balls, they had a similar FG%, an improved 3P% (+1.94%), and a much better FT% (+3.67%). There was also a noticeable difference when using Under Armour balls: Nike teams shot an improved FG% (1.47%), but worse 3P% and FT% (-2.25% and -1.26%, respectively) when compared to playing at other Nike schools.
While the averages of all the schools provide a good insight into the trends, we dove deeper to look at the individual Nike schools to calculate how many of them had drastic differences in shooting percentage.
Figures 1-3 show how Nike schools, on average, faired in the difference in FG%, 3P%, and FT% between home games (vs. all power 5 teams) and away games (vs. all power 5 teams, segmented by brand). The far left of the graphs denote a mean decrease of more than 10% in shooting percentage while the far right shows an increase of more than 10%. The middle of the graphs represents small changes in mean shooting percentage.
Figure 1 Nike Schools: Home vs. Away FG%
When playing other Nike schools, there was less variance in FG% (the more compact blue shape above), with most between -4% and +2%. When Nike schools visited schools using Under Armour, they were more prone to have either really good (+10%) or really bad (-6%) changes in FG%.
Figure 2 Nike Schools: Home vs. Away 3P%
Three point percentage had much greater variation. When Nike schools used Under Armour balls they shot at a 10% or greater decrease nearly 30% of the time. Nike schools were more comfortable chucking the long ball when they played schools using Nike or Adidas balls.
Figure 3 Nike Schools: Home vs. Away FT%
Again, the graph shows how erratic Nike schools’ average FT% was when using Under Armour balls. Under Armour balls were responsible for a higher percentage of both increases and decreases of more than 10% between home FT% and away FT%. However, the percentage of schools with > 10% decreases in FT% was much higher than schools with increases of > 10%. Nike schools were most comfortable shooting FTs with Wilson basketballs when on the road, even more so than Nike balls.
You Make Shooting Fun
In our above analysis, a hypothesis could be made that players know they are using a ball they don’t like and therefore will only take higher percentage shots. To further explore this hypothesis, we examined shot attempts. As with the previous analysis, our baseline is the difference in home shot attempts and away shot attempts when playing at another Nike school (Table 3).
Table 3 Nike Schools: Mean Difference in Attempts From Home (Percentage)
Surprisingly, Nike schools, on average, had 3.75% and 2.43% higher FG and 3 point attempts on the road vs. other Nike teams than at home, respectively. Using this as the baseline difference between home and away play, we then looked at how Nike schools shot in gyms using Wilson, Adidas, or Under Armour balls. Nike schools attempted less field goals when using Wilson (-1.75%), Adidas (-5.06%), and Under Armour (-5.51%).
When 3 point attempts were considered, Nike schools were apt to shoot more when using Wilson balls than Nike balls when on the road (1.1%). This did not occur with Adidas or Under Armour schools. When Nike schools visited schools using Adidas or Under Armour, they shot 2.38% and 5.44% less 3 pointers than when they visited other Nike schools, respectively.
Diving deeper into this, we again looked at how the individual Nike schools averaged in FG and 3 point attempts while on the road. Consistent with Table 3, in general Nike schools attempted more shots while on the road regardless of the opponent’s brand of basketballs.
Figure 4 Nike Schools: Difference in FG Attempts From Home (Percentage)
Nike schools were again much more comfortable with Wilson balls than even their own brand when on the road because they averaged more FGAs. Again, it was all or nothing for both Under Armour and Adidas with a high percentage of +10% or -10% changes in FGAs.
Three point attempts (Figure 5) were even more radically distributed than FG attempts.
Figure 5 Nike Schools: Difference in 3P Attempts From Home (Percentage)
More often than not, teams either shot 10% more or less than their home average regardless of the opponent’s sponsor.
Now, before you scramble to dig up your bracket and see how this would have changed your predictions – the NCAA tournament is played with a standard Wilson ball and Nike schools faired quite well using Wilson balls: they had a similar FG%, and improved 3P% (+1.94%), and much better FT% (+3.67%).
So does the brand of ball make a difference? Probably more so in shooting strategy than shooting efficiency. While efficiency numbers only vary about 2% in most categories, the number of attempts for both FGs and 3 pointers has significant differences when Nike schools use Adidas or Under Armour balls.
There are many other variables that may give the home team an advantage such as the color of the court, elevation or structure of the arena, and perhaps greatest of all fan involvement. Perhaps Under Armour schools have more fans behind the basket intimidating shooters during a free throw? When this data becomes available we’ll be sure to add it to the analysis.
 “CBB at Sports Reference.” College Basketball at Sports-Reference.com. Sports Reference LLC, n.d. Web. 20 Mar. 2016.
 Strelow B. “In light of Deflategate, lack of a universal ball in college hoops has bearing in ACC”.
The Fayetteville Observer.
January 30, 2015.