How eFG Percentage Can Trick You

Stats can be misleading. In fact, you might see a trend from a statistic based on a strategic adjustment you made. And you view the trend as a positive thing, so you stick with your strategic change.

However, you are actually losing more games because of this change. It's impacting other aspects of the game as well.

From a simplistic perspective, your offense can affect your defense, and your defense can affect your offense.

Let's take a look at an effective field goal percentage and see how this might happen.

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.

Shoot A Lower Percentage And Score More Points!

Coaches really like this eFG% because you can shoot a lower percentage, but score more points.

Let's take a look at an example and how this can possibly deceive you.

When you played the same opponent during the season, you noticed this occurred. Note, we're going to exclude free throws for the point totals.

Game 1 - You shot 52% and scored 53 points.

You made 26 of 50 shots. You made 25 two-point shots and one three-point shot.

Game 2 - You shot 44% and scored 58 points.

You made 22 of 50 shots. You made eight two-point shots and 14 three-point shots.

Well, the eFG% was higher in game 2!

The knee-jerk reaction is that you need to shoot a higher volume of 3-point shots, like in game 2. Even when you missed more shots in game 2, you still scored more points.

	Game 1	Game 2
Made Shots	26	22
Missed Shots	24	28
FG%	52%	44%
Made 3-Point Shots	1	14
eFG%	53%	58%
Total Points	53	58

HOWEVER... There Is More To The story. You Still Lost Game 2!

As you evaluate the two games even more, you realize there were some other consequences that affected the game.

Game 1 - The opponents only scored 48 points, and you won the game.

Game 2 - The opponents scored 60 points, and you lost the game, even though you had a higher eFG%!

Simple, right? You just played bad defense.

However, when you watch game film. You noticed that your half court defense looked better in the loss (game 2) than in your win (game 1).

Then you noticed something else. Your opponent was getting a lot of fast break opportunities.

In fact, your opponent had 10 additional fast break points in game 2.

Then as you analyze things further, you noticed 80% of their fast break points came off of 3-point shots due to the long rebounds.

So not only were you giving the offense more fast opportunities, you were giving them better fast break opportunities.

	Game 1	Game 2
Made Shots	26	22
Missed Shots	24	28
FG%	52%	44%
Made 3-Point Shots	1	14
eFG%	53%	58%
Total Points	53	58
Opponent's Points	48	60
Opponent's Fast Break Points	5	15
Opponent's Fast Break Points - Off 3 Pt Shots	2	12
Outcome	Win	Loss

Your Opponent's Best Player Played Way Better In Game 2

You also notice that their best player was a much bigger factor in game 2.

The player scored 24 points and scored their last 6 points in the final minute to beat your team.

Where in your victory (game 1), they only scored 8 points. They only played 16 minutes due to foul trouble. They were also more tentative and out of sync because of this.

Well, why did this happen?

In game 1, you were a lot more aggressive attacking the basket and even feeding the post. You took fewer 3-point shots.

Stop Taking 3 Point Shots?! Nope...

Now, this example isn't meant to discredit taking three-point shots and looking at the effective field goal percentage.

However, you need to look at the big picture. You can't look at one offensive stat and assume there aren't other consequences.

In this article's example, you might find that tweaking when and where your 3-point shots are attempted improves your results.

Maybe you want to take more 3-point shots early in the possession before the defense gets back.

1 - This could help because more of your slower players are further from the basket and in a good position to transition back on defense.

2 - Additionally, maybe you don't have a super athletic team. But you have one or two athletes that are great at getting up and down the floor. This allows them to crash the offensive boards and get more rebounds because they are going against fewer defenders.

Perhaps, you want more 3-point shots from the corner because the misses don't bounce as far towards half court. Thus, giving your defense more time to get back and reducing high-percentage fast break opportunities for the opponent.

Additionally, evaluate your individual situation. Just because something works for the Golden State Warriors, Duke Blue Devils, or UCONN Huskies doesn't mean it will work for you.

It doesn't matter how your past teams have performed doing X. It doesn't matter what college stats, NBA stats, or stats from any other level might tell you.

These stats can help guide you, but you need to figure out what works for the team that you are coaching.

Resource: Breakthrough Basketball Stat Tracking App For Coaches and Parents

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