The Fallacies of eFG%

"Judge your success by what you had to give up in order to get it." - Author Unknown

What is eFG%?

eFG% is a field goal percentage measurement that counts 3-pointers as 1.5 field goals. So for example, if Kobe Bryant converts 4 of 12 baskets, all 3 point shots, his FG% is 33% and his eFG% is 50%. And, if LeBron James makes 6 of 12 shots, his FG% and eFG% are 50%. Both players score 12 points in this scenario.

The formula looks like this: eFG% = (FGM + .5*3PM)/FGA

eFG% is useful for describing a player's shooting efficiency. Both Bryant and James used 12 shots to net 12 points and by this method, Bryant is not penalized for attempting the more valuable 3-point shots. Both players are deemed equally efficient shooters.

So where does eFG% fall short?

eFG% doesn't recognize the impact of success and failure. In the example above, Bryant failed 8 times by missing 8 shots while James only failed 6 times. Hence, Kobe's 50% eFG is not equal to LeBron's 50% eFG when considering conversion rates. Given the choice, I would always consider the higher conversion rate as more valuable.

Why make the distinction when both players scored 12 points on 12 attempts?

Because succeeding is more valuable than failing and missing shots is detrimental on many levels:

1. Missed shots kill team momentum. Basketball is a game of runs and nothing ends a run quicker than sending one off the side of the rim. Conversely, swishing one through the net only adds to momentum, rhythm, and player confidence.

2. Missed shots reduces crowd enthusiasm. How many times have we seen crowd excitement grow with each successive basket only to be deflated by a failed attempt?

3. Missed shots often result in over-the-back fouls (on the bigs) or reaching fouls (by the disappointed shooter).

4. Missed shots are a success to the defensive team and a victory to the defensive player (hardly feelings you want your opponent to enjoy).

5. Missed shots are a golden opportunity for the defensive team to initiate a fast break which leads to easy baskets.

Imagine missing 8 of 12 shots against the 2007 Phoenix Suns, a team that looks to run on every posession. Giving the explosive Suns eight opportunities to push the temp is a dangerous proposition.

Conversely, making a basket gives your defense time to set for the next possession, not to mention all the other intangibles that result from made field goals.

Conclusion

eFG% should not replace the traditional FG% measurement because it ignores the impact that missing shots has on a basketball team. Critics will argue that eFG% is a more accurate measurement. And, from an individual perspective, they are correct. But, basketball is and always will be a team game, and as such, overlooking the effects of success versus failure is not a viable option.