Late one night, in the fall of 2019 when the world was normalish, I was in a dark basement and was wondering what the free throw percentage was for guards vs forwards. You know, Bigs vs Smalls. Was there a difference? See, it was taught to me that Bigs aren’t great free throw shooters. It is hard for me to remember a “big” that was good at shooting FT (but we are going towards position-less basketball… isn’t Luke like 6/7″? Also, hard for me to remember a big guy going to the line for his team as the best free throw shooter – aside from Anthony Davis, which is recency bias). I determined to do some analysis and it morphed into a long twitter thread (which doesn’t matter and neither does this, but I am doubling down on my efforts as they will not stay in a google sheet forever) and me asking myself does it really matter? And it does. Knowing matters.
First thing to know is that free throw percentage since the beginning of basketball time hasn’t changed much; it has been right around 74-75%. However, those first few years were really brutal as they were hitting sub 70’s, but they quickly ascended the mountain and it has maintained. See the image below. This is pretty remarkable. How has the average basically been in the same range for 30 years?
Free Throw % average for the league in given year
Let’s get a little more granular. Looking at the NBA regular 2016-2019 seasons data from ESPN, I broke the data down by minutes played avg. in 5 min increments and positionally (Small – PG, G, SG, SF; Big – PF, C). The original question was is there a difference between FT % of smalls v bigs, but a major factor is time played. Any good shooter knows you need to find your rhythm. James Harden wouldn’t get to the FT line as much as he does if he played just 15 mins a game. Now, while that is obvious, I wanted to see what the data actually showed.
Increased playing time directly correlated with better FT %
As suspected, players that are on the floor for the majority of the game are better free throw shooters. The standard deviation in free throw percentage based on time played also drops with more playing time. This would make sense, as your better players will be on the court longer, will have more time to be in rhythm of the game, and more opportunities to shoot free throws. There is more variability with a player who doesn’t get a lot of playing time.
Guards are better free throw shooters, no matter minutes played
In the above chart it is clear that guards are indeed better free throw shooters regardless of time played. Bigs close the gap at 35+ minutes, but otherwise are below 75% behind the stripe. Guards on the other hand are never below 75% and are above 80% for under 10 minutes and more than 30 minutes. This become even more evident in the below chart (which is a bit like a spaghetti dish, forgive me). Notice the red line of the Center and the consistency of the blue line of Guard.
Wide Swings for Centers with greater playing time
Here. Let’s look at the same chart with less positions. What is clear is there is an outlier in our Center group who is raising the FT% up; it’s Anthony Davis.
It is clear to see that with more time played, players are better free throw shooters. The correlation of avg mins played to FT% is 0.23. All be it a moderate correlation, it is there. Additionally, the best players are the ones on the court towards the end of games and attaining more minutes.
PG/SG as suspected are generally the guys you want taking FTs. These players should be close to 80% on their FT %. The small forward position seems to be the is the star position, with guys like LBJ, KD, PG13, Kawhi, etc
Ok. So we know who the better FT shooters are. But what explains the average FT % being in the mid 70’s? Take a gander at the below charts… Essentially, Bigs take more FT per game with a poor FT %.
If we combine the positions into big v small we can see that 41% of FT were shot by a big, while 58% were smalls.
Some other things to consider.
- Guards get to the FT almost every 6 minutes, while Centers go almost 9 minutes
- The best way to optimize a rotational players and see their contribution is for them to get a few minutes a hit some FT
- The correlation of FTA & FT% is just .13
- James Harden is listed as a point Guard. He led the league in FTA for this data set. And aside from the 2017 season (Russell Westbrook) a Center or Power Forward was #2 on the list
