How stretch in defense yields efficient offense (part 1: FG%)

January 4, 2017 by J.H. Yeh

In the previous couple articles we discussed in depth why teams are reluctant to invest on mid-range experts because 3-point field goals generate higher returns in the long run. Moreover, we also talked about why teams are avoiding to construct a “big” roster that can rebound very well because teams are shifting focus from second chance possessions to transition defense. These change in taste, or shift of playing style, reflects on the general tendency that today’s NBA is trending small lineups that usually feature just one big man, who’s primarily responsibility is to protect the rim and secure defensive rebounds. Click here for the complete article.

On one side of the spectrum, we have the Chicago Bulls, who are struggling with shooting due to the dearth in perimeter shooters and abundance in rebounders. On the other side, we have the Houston Rockets and the Golden State Warriors, who are making shots from literally all over the floor thanks to their perimeter shooters. Previously, we briefly mentioned how perimeter shooters can stretch the floor. In this article, we will go into more details on the added value of 3-point shooters. Or more specifically, how perimeter shooters can force the opponent to stretch the defense, hence spacing the floor and executing efficient offense.

It’s no secret that the more 3-point field goals are attempted, the more likelihood the total scores will improve because if you shoot more, then you tend to make more. Of course, this is not always the case as you can assemble the worst 3-point shooting roster and have them to shoot a lot of 3s. Below is a chart that shows the positive correlation between shooting 3-pointers and total points scored.
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The results are somewhat mixed because there are other factors that confound the result. One of the major factors is efficiency. Other factors that may confound the result include the execution and the quality of the opponent’s defense. For a winning team like the San Antonio Spurs, they don’t shoot a lot of 3s but they are very efficient — and we will get back to that later.

The chart below plots the 3-point attempts per game and the 2-point field goal percentage. As a result, we can see a general tendency that shooting more 3s can improve the 2P% because by stationing more men on the perimeter can “stretch” the opposing team’s defense. By spacing the floor, the defense can become “porous” which can provide more space for players to drive for layups or pass the ball to a cutting player for an easy dunk. The Warriors are leading the league in 2P% by shooting an absurd 56.9% in the interior. Similarly, the Rockets are the second in that category at 54.1%. This statistic is as of January 5, 2017.

The chart shows that five of the six teams that shoot more than 30   3-point field goals will also shoot above 50% in the 2-point territory due to the “loose” defense. The Cavaliers are shooting just a hair below 500% (49.9% to be exact) and we will let them slide… for now. The Mavericks are the only team that doesn’t shoot above 50%. And in fact, they are nowhere near that benchmark. They are shooting at a putrid 47.7% in the 2-point region which is ranked 24th in the league. The Mavericks show that shooting a lot of 3s does not equate to effective 2-point shooting, which can reflect that the Mavericks are not stretching the floor enough due to their own inefficient shooting in 3-point field goals. The Mavericks are shooting 30  3s per game, good for seventh in the league; however, when it comes to making the shot, they are making just 34.9% of them, which is 21st in the league in that department.

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Now let’s look at the efficiency of 3-point field goals and how it can influence 2-point field goals. Teams close to the top right corner are the teams strong in making both 3-point field goals and 2-point field goals whereas the lower left corner indicates poor shooting in both 3-point field goals and 2-point field goals.

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As discussed in the last article, the Bulls are struggling with making 3s because none of their starting fives are perimeter shooters. Jimmy Butler is passable with a pedestrian 33.1%  (the league average in 3P% is 35.8%). Still, he is not considered a legitimate floor spacer.

The top two teams in making 2-point field goals are the Warriors and the Rockets because of their ability to successfully stretch the defense by allowing space for players to drive or cut into the basket. Moreover, because these two teams feature small lineups, they draw very few defenders into the paint because they keep the defenders honest by stationing on the perimeter.

On the other hand, the Bulls, despite featuring Robin Lopez and Taj Gibson, who can finishing strong near the basket, and all-star player Dwyane Wade, who is known for his drives and explosive cuts into the paint for easy baskets, the Bulls are not only struggling with their 3-point shooting (ranked dead last in 3PA, 3PM, and 3P%), but they are also struggling with scoring inside the 3-point line, making 47.4% of them, which is second to last in the league. The Bulls’ roster construct is the complete opposite of the Rockets’ and the Warriors’ because of their inability to space the floor. With a roster that features no range players and two bigs in Lopez and Gibson, the opposing team simply crowd the paint, which obstructs any potential drives and cuts to the hoop. For another word, a team that cannot shoot from the perimeter usually struggles with scoring from the inside as well due to too many bodies in the paint which greatly reduces offensive flexibility and options. Similarly, the Memphis Grizzlies also share the same dilemma as the team features just four floor spacers who are shooting above 37% in 3s. Moreover, the Grizzlies  have two elite scoring big men in Marc Gasol and Zach Randolph, who, instead of aiding to stretch the floor, induces the defenders to do the complete opposite by further tightening the interior defense. With high defensive concentration in the inside and poor shooting from the outside, the Grizzlies are currently ranked last in both 2-point field goal percentage at 45.7% and overall field goal percentage at 42.3%. To sum up, a competitive team should complement one (or sometimes two) interior player with floor spacing shooters or else the efforts will go into waste. Lacking perimeter shooters to assist in stretching the defense and opening up the floor for flexible offense can cause general inefficiency in offense because the defenders are all clogging in the paint.

A famous example of how stretching the defense can yield more efficient scoring is the 2013 NBA Finals. The matchup between the Miami Heat and the San Antonio Spurs offers an insightful look at the importance of floor spacing. In the first three games of the series, the Heat’s starters were LeBron James, Dwyane Wade, Chris Bosh, Udonis Haslem, and Mario Chalmers. With only one shooter on the court in Chalmers, the Spurs’ defensive strategy against the Heat was to clog the paint to prevent James and Wade from driving to the basket. Daring James and Wade to shoot from the perimeter, the Spurs succeeded in their approach by winning two out of the first three games. In the fourth game, the Heat replaced Haslem with Mike Miller to provide more floor spacing and the result is winning the NBA championship in a highly competitive and memorable series. The Heat’s switch on the starting lineup arguably changed the 2013 NBA Finals. Conclusively, this shows that when floor spacers are on the court, the defense is more stretched which allows more drives and cuts in the offense. As a result, stretching the defense can yield efficient offense.

This article only scratches the surface of how spacing the floor can generate efficient offense. Next, we will talk about what does it mean by efficient offense as we go beyond just the field goal percentage.

— J.H. Yeh

(all graphs are created by me, and all sources of stats are courtesy of NBA.com and BasketballReference.com as of January 5, 2017)

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