This week I was texted by a coach asking what impact the new three-point line will have on the game, and how it will affect the strategies behind shot selection. This is the exact type of question coaching staffs need to think about as they prepare and adjust for the upcoming season. The new three-point line was recently announced by the NCAA, moving the three-point line back to the international distance after experimenting with it in the 2018 and 2019 National Invitation Tournament. This approved rule change moves the line from 20’9” to 22’1 ¾”, which translates to a roughly 1’5” change in distance. The NCAA’s goal is clear – they would like to reduce the value of the three-point shot and, in turn, weaken the growth rate of three-point attempts. The chart below shows the rise of the three-point attempt rate in the college game. In the press release announcing these changes, the NCAA stated, “The 3-point shooting percentage of teams in the 2019 NIT was 33%, compared with their regular season average of 35.2%.” Their statement suggests that the D1 average should see about a 2.2 percentage point drop-off in 3P%. However, the NCAA’s attempt to interpret the impact of this change on shooting rate is poorly founded. Simply using the NIT tournaments data is not enough to understand the impact of a distance change over the course of a season. First, there is a sample size issue. There were only 31 games played in NIT in 2019, which doesn’t provide us with enough data to comfortably project next year’s three-point percentage. Second, the comparison made between regular season and tournament shooting percentages is misleading. Teams play easier competition throughout the year than they do in tournaments, which causes tournament shooting percentages to be lower than regular season percentages. Proof? Look no further than the NCAA tournament. The chart below compares the shooting percentages of NCAA tournament teams in the regular season versus NCAA tournament games. NCAA tournament teams shot 1.3 percentage points worse in NCAA tournament games than they did in the regular season. The distance wasn’t changed. The competition changed. The more logical and accurate way to measure this impact is to use shot distance data. Using shot distance data from last season, DribbleHandoff analyzed the projected drop-off from moving back about 1'5". This analysis showed that the D1 average decreased from 34.4% to 33.7%, a 0.7 percentage point change. Examining shots attempted between 21 to 26 feet (which accounts for over 90% of threes), the largest drop-off in any 1-foot increment is 1.2 percentage points. Therefore, even using the most extreme difference puts us below the NCAA’s suggested 2.2 percentage point drop. The question then becomes, how does this impact the value of a three-point shot in relation to the other shots? To compare shot locations, it is best to use expected point value, which is calculated by simply multiplying the shooting percentage of a given area by the points the shot is worth. For example, last season, threes were made at a 34.4% rate and are worth 3 points, so the expected point value is 1.03. The chart below uses data from the last five years to compare the expected point value for shots at the rim, midrange shots, and threes. Over the last five years, shots at the rim are the most valuable shot. Threes were only .15 expected points behind these rim shots, while midrange shots were drastically less valuable. The estimated three-point shooting percentage given the new three-point line is roughly 33.7% based on last year’s data, which translates to an expected point value of 1.01. This is about a .03 expected point decrease versus the last five years. The difference between shots at the rim and threes is now more pronounced as the expected point margin will move from .15 to about .18. Threes are still a highly valuable shot at this percentage and therefore defenses will be forced to defend an even larger area, which will provide better spacing. This could lead to shots at the rim becoming even more efficient. In the same press release, the NCAA stated the following as one of their motivations for the distance change: “Slowing the trend of the 3-point shot becoming too prevalent in men’s college basketball by making the shot a bit more challenging, while at the same time keeping the shot an integral part of the game.” If a team reduces their three-point attempt rate and instead takes more shots at the rim, especially given good spacing, then that is a valuable trade-off. However, many analysts have suggested that players should now develop their mid-range game and should prepare to shot fake from the perimeter and take a few dribbles in for a mid-range jumper. This is the trap of the new rule change! Teams shouldn’t trade threes for mid-range shots because of this rule change. Even with the slightly lower shooting percentage from three, these shots from beyond the arc are still worth .29 expected points more than mid-range shots. Over the last five seasons, the college game has made great strides in reducing the percentage of shots that come from the mid-range area. As I shared at the 2019 NABC Convention, I built a model which shows that a team wins one extra game, on average, for every five percentage points decreased in mid-range attempt rate. What should teams do with the 21-foot jump shots that they took last year when they were still worth three points? Reallocate them to either shots at the rim or a new three. Anything but using them to fund more mid-range shots. There will be teams that are influenced by the way the NCAA presented this rule change in their press release. Don’t be misled - increasing the mid-range attempt rate will only cause teams to be less efficient and win fewer games.
1 Comment
4/22/2020 02:18:38 am
This strategy is definitely one of the best if you want to score the basket. There are people who do not understand just how important it is to go and use tactics to score. If you cannot score through talent alone, then you have to rely on tactics. This strategy will take time to master, but it is pretty effective. I was able to make a championship team out middle schoolers just through the use of this strategy, believe me, it works.
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