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What is Effective Field Goal Percentage?
- By Jeff Haefner
And Why YOU Should Use It
Effective Field Goal Percentage is a measurement of how successful your team is from the field. This metric provides a more complete picture of the game situation than standard field goal percentages because three point shots are given extra weight.
How Do We Calculate It?
Effective Field Goal Percentage, or eFG%, is calculated the following way:
(2pt FGM + 1.5*3pt FGM) / FGA
This means a made three-pointer is worth one and a half times as much as a made two-pointer. A player who shoots 4 for 10 on all two-point baskets has a standard FG% of 40% and an eFG% of 40%. But, if all those makes were three-pointers, that player’s eFG% is 60%, reflecting the extra value of a made three.
In a real game of basketball, what matters is points scored per possession. A player whose eFG% is 60% is scoring at a rate equal to shooting 60% on two-point field goal attempts, a very respectable number.
Why Do We Highly Recommend this Metric?
The Effective Field Goal Percentage can tell you at a glance which team is having more success from the field. The team with the higher percentage is scoring more effectively from the field.
eFG% is what I would call a “high level key indicator”. Other high level indicators include:
- Field Goal Attempts
- Free Throw Attempts
- Free Throw Percentage
If you beat your opponent in all 4 high level key indicators, you will always win. From a winning standpoint, are there any metrics that are more important?
You could argue that eFG% is the most important stat because in a typical game the majority of points are scored from the field. If you have a high eFG% and your opponent has a low eFG%, then both your offense and defense is probably doing quite well. And you have a really good chance to win.
Of course rebounds, free throw attempts, and field goal attempts are all important and affect the outcome of the game. But if I could only choose one stat to be really high, I would choose eFG%.
The Sabermetrics of Basketball
In the book, Basketball on Paper (which is basketball's version of Moneyball and an excellent book), Dean Oliver identified what he called the "Four Factors of Basketball Success":
- Shooting (40%)
- Turnovers (25%)
- Rebounding (20%)
- Free Throws (15%)
The number in parentheses is the approximate weight Mr. Oliver assigned each factor. Shooting is the most important factor, followed by turnovers, rebounding, and free throws.
The Four Factors were based on Oliver's extension research of the stats behind winning teams. He claims that shooting is the most important factor. I agree.
How to Use eFG% as a Coaching Tool
One of the simplest ways to effectively utilize eFG% is to look at the differential compared to your opponent. You can look at the differential for a single game, multiple games, or an entire season.
To show you what I mean, here’s a screenshot from our basketball stats app:
You’ll notice a differential of +20%. In this case, my team is Iowa and we want positive differentials. A positive number tells me that my team is winning in the statistic. And in this case we’re winning by a significant margin!
This allows you to quickly glance at the differential and you’ll know precisely how your team is performing in that area.
If you are getting beaten badly, then you need to figure out why your eFG% is lower. Then figure how to remedy the problem by making adjustments to your defense and/or offense.
By looking at the eFG% differential, you immediately get a completely objective indication of how you are performing. There is no guesswork. And you can make informed and strategic decisions as a coach.
How Does Your eFG% Stack up to NBA, College, and High School Teams? What Should You Expect?
Just to give you a reference point, here are eFG% stats from various levels...
In 2013, the average eFG% for the NBA was 49.66%. The Miami Heat has the highest eFG% at 55.24%. Guess who had the second highest eFG%?
The San Antonio Spurs had the second highest at 53.06%. These were the two best teams in the NBA and met in the finals!
Is it a coincidence that the teams with the two highest eFG% also had the best records and made it to the finals?
Seems to me like yet another bit of evidence that eFG% is an incredibly important stat.
Note: I tried to find stats for WNBA but couldn’t find it.
In 2012/13 season, Creighton had the highest regular season eFG% at 58.2%. Howard had the lowest at 39.2%
I did a quick search for women's numbers but couldn’t find them.
High School and Youth Stats
Last year I coached a 9th grade boy's team that had a 49.5 eFG% for the season. We were undefeated for the season.
The previous year our 9th grade team had a 41.5 eFG% for the season. We won around half of our games.
Hopefully this gives you a little idea of what you can expect regarding numbers.
eFG% has become an important stat for me as a coach. I hope this article gives you some ideas and might allow you to utilize this simple metric to help you as a coach to win more games.
What Other Stats Do We Recommend?
As you can tell, we believe eFG% is one of the most important stats you should use as a coach. But that’s only one stat.
Please leave your comments, suggestions, and questions below...