Around NBA draft time, you may hear analysts discuss prospect shooting ability and the ability to develop a 3-point shot. Here we’ve taken an attempt at using historical NBA data to prove or disprove whether players improve their 3-point shooting over the course of a career.
To try and see if 3-point shooting percentages increased over the course of a career, we plotted 3FG% against player career year. Looking at the charts, there does appear to be a positive trend on 3-point shooting in aggregate. However, when you consider that fewer and fewer players make it to the next career year, it is the better players that are proceeding on, and they will usually be your more skilled players (including 3-point shooting). Was that ever-decreasing pool of players already better shooters, or did they improve over time?
The two charts below show 3-point shooting percentages by career year and the number of players that qualified – shooting at least 75 3FG in career year.
To examine how influential the smaller player pool impacted the positive trend, we looked at trend lines for each player individually. Of the 958 (the total is higher than any single bar because different players qualify in different years) players analyzed with at least one season of >=75 3FGA, 322 players showed negative sloping arcs, 415 showed positive sloping arcs, and 221 either had no change in percentage or only one season with at least 75 attempts. If we look at only percentages that change, historic evidence shows that 56.3% of the time, players will increase their 3FG percentage over the course of their career (and 43.7% will see percentage decreases.) The slopes for increasers and decreasers is roughly equivalent in absolute terms. Decreasing percentage players saw an average coefficient on Career Year of -0.0159 while increasing percentage players had an average coefficient of 0.0147. This would have to be researched further, but the stronger slope may also correlate with earlier retirement than those increasing percentage.
Individual Player Snapshots
Below are some selected individual player career arcs. Rather than using dots to represent data points, charts are shown as lines with the dotted line being the trend. Players shown are Dirk Nowitzki, Kobe Bryant, Ray Allen, Kyle Korver, LeBron James, Paul Pierce, and Lamar Odom.
Potential for Increased 3FG% During Career
For those that do see an increase over time, how much could be expected? The two charts below show the spread between max career 3FG% year and min career year, as well as max vs. median. In both charts, the bottom portion depicts the spread value (either max minus min or max minus median). Using max in this analysis is probably an overly aggressive approach because the player will achieve that value of the 3FG% only once in their career. However, if you compare max with median, this could give you a sense for what NBA teams should realistically hope to achieve in player development.
As seen in the max vs. median chart, the highest values come in around the 0.13 or 0.14 range. An average number would be around 0.05. Therefore, what this is saying is you would hope that if you sign a free agent, or are developing someone on their rookie contract, that you’d be able to improve their 3FG% by around 0.05.
Correlation with FT%
We also took a look at how correlated 3FG% and FT% are correlated as many draft experts will use FT% as a projection for 3FG% potential. They are certainly correlated, but there are many outliers. The chart below depicts 3FG% vs. FT% as well as 3FG% vs. 3FG Attempts.