A New Way to Quantify Scoring Efficiency: Accounting for Both the 3 and Free in Today’s NBA

The days when merely putting up gaudy scoring numbers got NBA players eight-figure yearly salaries are almost behind us (Rudy Gay is the last of a dying breed). Front offices are realizing that to win in today’s hyper-competitive league, their scorers must also put the ball in the hoop in an efficient manner. We saw an example of a team wising up just this offseason when the lovable Bucks of Milwaukee happily watched their two high-volume, low-efficiency gunners leave for new cities (that are praying they can fix each player’s shot selection issues). By the way, both players were certain they would receive one of those juicy eight-figure salaries, but had to settle for a couple million per less.

“Moreyball” is taking the league by storm and taking advantage of the two most efficient shots in basketball: the 3 pointer and the free throw. And today’s advanced metrics only show positive signs for this new strategy. Here are last season’s 10 best offenses based on Offensive Rating (courtesy of Basketball Reference) along with each team’s 3PA rank and FTA rank:

ORtg

Out of the ten top offenses there are seven that finished in the top-10 for 3PA and seven that finished in the top-10 for FTA. And, excluding the Jazz, every team is either near the top in both categories or dominant in one of the two.

Currently, most public advanced stats and analytics websites use eFG% (effective field goal percentage) and TS% (true shooting percentage) to show the increased efficiency in players and teams that take advantage of these two types of shot attempts. The problem is, neither one of these metrics figures both free throws and three pointers into their respective equations. eFG% only rewards three point marksmen for their accuracy while TS% mainly benefits players who draw contact during their shots and get to the line.

eFG_TS

A new metric is needed in order to quantify the combined effect of a player’s shots from deep and trips to the line. A potential metric that I have named Weighted Scoring % (WS%) does just this by weighting each type of shot in relation to the reward for a make. Here is the equation used to calculate a given player or team’s WS%:

WS

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Now, check out the NBA’s Top 25 players in each of these shooting metrics for the 2012-13 season. I have only included the 206 players who appeared in 50 or more games and also played 20 or more minutes per game.

compchart

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We see a lot of player overlap when using these metrics, but there are a couple problems that arise when using both eFG% and TS%. eFG% does not reward scorers who cash a large majority of their points in at the free throw line. Because of this, James Harden, the focal point of the potent Rockets offense, ranks 88th out of qualifying players in eFG%. In contrast, players who struggle from the line (like DeAndre Jordan and Andre Drummond) are not punished for their inefficiency in this area. Thus, we see both of these players finishing in the top 4 of the league. TS%, on the other hand, ends up over-rewarding players who shoot a lot of free throws. For example, a player that goes 11/12 from the line for 11 total points will have a TS% of 1.04 while a player that goes 6/6 from the field for 12 total points will have a TS% of 1. This is why we see Harden jump into the top 20 and other floppers who take a high percentage of their shots from the line (CP3 and Bosh) also rise in the rankings.

WS% properly quantifies a player’s scoring efficiency by taking into account the points given for making each type of shot (2P, 3P, and FT). This is why we see a player like Stephen Curry, a highly accurate shooter who takes a lot of threes but not too many free throws, jump up to the 16th most efficient scorer in the League.

When we add a constraint to only include the 95 players who shot 10 or more FGA per game (along with the other two previous constraints) we get a better idea of who the best high-volume, high-efficiency scorers in the NBA are (I included the top 10 and some select other players):

rank

Keep in mind that the average WS% for the League during the 12-13 season was 0.528. This means that offensive cogs like LaMarcus Aldridge and Al Jefferson were scoring at below league average efficiency rates. Unless your team is sporting a top-of-the-line defense like Chicago, Memphis, or Indiana (and even then) it is difficult to win with your offense revolving around chuckers with bad shot-making percentages and/or poor shot selection.

The best offenses and teams in the League (Heat, Thunder, Rockets, Clippers) boast at least a couple of highly effective scorers who draw fouls and knock it down from deep. This trend is not changing any time soon. Look for the number of 3′s taken in games to continue to rise along with, unfortunately, the number of flops to get to the free throw line. These are the shots that win championships, and front offices are starting to notice.

(Via Luke Baker, Hoops-Nation.com)

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