Can Students Affect Free Throws?

Author

Paul Sabin 

finished season  2015 
finished season  2016 
finished season  2017 
finished season  2018 
finished season  2019 
finished season  2020 
finished season  2021 
finished season  2022 
finished season  2023

Background

  • College basketball has among the largest home court advantages in all of sports.
  • Student sections have been getting increasingly creative in their attempts to affect the outcome of opposing team shooters making their free throws.

Previous Research

  • Duke medical student tabulated the miss percentage for games in the 2020-2021 and 2021-2022 seasons for various different distractions the graduate student section makes behind the basket in the second half.

Previous Research

Duke’s “Cameron Crazies”

Previous Research

  • Arizona State is known for its “curtain of distraction” which rose to fame in 2015 and even had a surprise distraction of shirtless olympian Michael Phelps.

Previous Research

  • The Harvard Sports Analytics Collective did a study in 2015 about the Arizona State “Curtain of Distraction”
  • Reported that visiting teams shot 60.6% from the free-throw line in the second half compared to 68.6% in the first half.
  • Estimated it was worth approximately 1.41 points per game.
  • Not a statistically significant

Previous Research

  • Harvard PhD student and author of the ncaahoopR package, Luke Benz revisited the Arizona State distraction in 2019 and found that there was not enough evidence to conclude that teams shoot worse against Arizona State than they do at other road games.

Data

  • Data from the 2015-2016 college basketball season until the current season’s data (2023-2024).
  • Home teams with less than 15 games in the dataset, grouped into one collective team.
  • Only look at true road games, not neutral site.

Data

  • Group all season’s together for the home team when assessing a fan base/court effect
  • But for the individual team shooting performances I treat each season separately

Methodology

Two methods I explore:

  1. Second Half vs First Half (shooting into a rowdy student section)
  2. Overall effect of a home court on free throw percentage

First Half vs Second

  • Not every team may put a large student section behind the second half visiting team’s basket
  • Want to assess if there is an effect for teams
  • Compare entire county to what we would expect due to randomness.

First Half vs Second

  • Only include teams with 200 free throws attempted at their home court in both the first half and second half in data set
  • Results of largest drop-off in free-throw percentage from the 1st half to the 2nd half

First Half vs Second

First Half vs Second

  • In fact, on average, visiting teams shoot 1 percent better in the second half than compared to the first.
  • Could be due to the effect of the end of game scenarios in basketball.
    • If a team is winning and getting fouled it does its best to get the ball into the hands of their best free throw shooters.
  • Hard to test this theory
    • Would need to go with free throw share by players conditional on time remaining and score.
  • I adjust p-values and z-scores by taking off an additional 1% of all 2nd half FT%

First Half vs Second

Visiting Free Throw % by Half
2015-16 to 2023-24 Seasons