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A.P. Hoops: The Three (point) Habits of Highly Effective Shooters

All season long, D-League.com will be looking at its top prospects and teams through the lens of advanced stats. Today, we focus on leveling the playing field between inside and outside scorers.

Gabe Pruitt, known as one of the NBA D-League's best shooters, needs a more advanced metric than FG% to measure his worth.
Dave Eggen/NBAE via Getty Images

Last week we discussed the key principles behind APBRmetrics and learned how to adjust for pace, allowing us to determine how efficiently players convert the opportunities they are given. If you need a refresher, AP Hoops 101 can be found here.

This week we'll start breaking down some of the specific statistics that comprise APBRmetrics -- a standard of measurement that, for our purposes, can pinpoint some great prospects that would otherwise be glossed over by the casual fan.

To introduce our next concept, let’s take a look at a very simple example. Let’s say the Iowa Energy's taking on the Los Angeles D-Fenders. Energy rookie phenom Jarrid Famous has his groove going in the post and makes six of his first 10 field goal attempts (FGA) from the block.

Using very simple math we determine that he would have a total of 12 points, and would have a stellar field goal percentage (FG%) of 60%. Now let’s pretend that his opponent, Brandon Costner, is feeling it from downtown and drills four 3-pointers out of his first 10 shots, totaling 12 points and giving him a FG% of 40%.

Now we’re left with a tough predicament. Both players have 12 points, and looking at their FG% would tell you that Jarrid Famous is a “better shooter” than Brandon Costner. But clearly there’s more to this story: 3-pointers are more difficult to make than 2-pointers, but come with the added reward an extra point.

So now we ask ourselves...

Is there a way to account for the difference in both difficulty and point value between 2-pointers and 3-pointers?

After all, both players in our example took 10 shots to score 12 points.

As you may expect, the glorious land of APBRmetrics has an answer: A simple solution called effective field goal percentage (eFG%).

This statistic is one of the cornerstones of statistical guru Dean Oliver’s “Four Factors of Basketball Success” (which we will address in more detail in future articles) and provides a much more accurate assessment of shooting efficiency. eFG% corrects the “3-point problem” by counting each converted 3-pointer as one-and-one-half made field goals to reflect the 3:2 ratio between a three-pointer and two-pointer.

For those who are wearing their thinking caps, the formula is as follows:
Effective Field Goal Percentage (eFG%)
Definition: Adjusted FG% accounting for fact that 3-pointers are a lower percentage, but worth an extra point.
eFG% = (FGM + 0.5 x 3PM) / FGA

So let’s use our previous example to make sense of this mathematical jargon.

Jarrid Famous
FGM = 6, 3PM = 0, FGA = 10
eFG% = ((6) + 0.5 x (0)) / 10
eFG% = (6) / 10 = 60%
Brandon Costner
FGM = 4, 3PM = 4, FGA = 10
eFG% = ((4) + 0.5 x (4)) / 10
eFG% = (4 + 2) / 10
eFG% = 6/10 = 60%

When you’re done having your Algebra I flashback or suffering from a quick bout of mathematical PTSD, you will realize that eFG% successfully equated the shooting efficiency performances of Famous and Costner to reflect the fact that each player scored 12 points with 10 shots.

Now we’ll roll up our sleeves and take a look at the top performers in the NBA D-League this season with regards to FG% and eFG% for players who have taken at least 30 shots. When examining the data below, note how 3-point shooters are noticeably absent from the FG% list but are featured prominently in the eFG%. Furthermore, you will notice that players who shoot many 3-pointers typically have the biggest discrepancy between FG% and eFG%. And pay special attention to the fact that only one player in the top five in field goal percentage (Rio Grande Valley forward Marshall Brown) appears in the top five in eFG%.

TOP 15 PLAYERS, SORTED BY FIELD GOAL PERCENTAGE (FG%)
Player FGM FGA 3PM 3PA FG% eFG%
Famous,Jarrid 52 83 0 0 62.7% 62.7%
Thomas,Lance 20 33 0 0 60.6% 60.6%
Lewis,Marcus 33 55 0 1 60.0% 60.0%
Garcia,Charles 31 52 0 2 59.6% 59.6%
Brown,Marshall 30 51 9 19 58.8% 67.7%
Coleman,Dominique 19 33 4 8 57.6% 63.6%
Harris,Terrel 39 68 10 24 57.4% 64.7%
Andrews,Zach 32 56 0 0 57.1% 57.1%
Asumnu,Stanley 45 79 0 0 57.0% 57.0%
Coleman,Sam 25 44 13 26 56.8% 71.6%
Fazekas,Nick 38 68 1 3 55.9% 56.6%
Anderson,Mike 22 40 0 4 55.0% 55.0%
Biggs,Tyrell 28 51 0 4 54.9% 54.9%
Pattillo,Juan 18 33 0 0 54.5% 54.6%
Hamilton,Brian 33 61 1 5 54.1% 54.9%


TOP 15 PLAYERS, SORTED BY EFFECTIVE FIELD GOAL PERCENTAGE (eFG%)
Player FGM FGA 3PM 3PA eFG% FG%
Coleman,Sam 25 44 13 26 71.6% 56.8%
Brown,Marshall 30 51 9 19 67.7% 58.8%
Harris,Terrel 39 68 10 24 64.7% 57.4%
Coleman,Dominique 19 33 4 8 63.6% 57.6%
Pruitt,Gabe 22 42 9 19 63.1% 52.4%
Famous,Jarrid 52 83 0 0 62.7% 62.7%
Allmond,Corey 19 41 12 26 61.0% 46.3%
Thomas,Lance 20 33 0 0 60.6% 60.6%
Lewis,Marcus 33 55 0 1 60.0% 60.0%
Thomas,Adrian 14 35 14 34 60.0% 40.0%
Fortson,Courtney 38 72 10 18 59.7% 52.8%
Garcia,Charles 31 52 0 2 59.6% 59.6%
Graham,Zach 26 49 6 17 59.2% 53.1%
Dentmon,Justin 19 39 8 17 59.0% 48.7%
Ehambe,Moses 48 96 17 35 58.9% 50.0%

Note: All data was provided by NBA StatsCube.