Beyond Standard Shooting
In traditional basketball statistics, a player who shoots 5-for-10 from the field has a 50% Field Goal Percentage. However, if Player A made five 2-pointers (10 points) and Player B made five 3-pointers (15 points), it is mathematically absurd to say they were equally efficient. Player B generated 50% more offensive value on the exact same number of shots.
Effective Field Goal Percentage (eFG%) corrects this mathematical flaw by explicitly weighting 3-point shots as 50% more valuable than 2-point shots.
The Mathematics of eFG%
eFG% strips away the noise of free throws to focus strictly on how efficiently a player is shooting the basketball from the floor.
The Formula
The formula adds a 0.5 multiplier to every 3-pointer made, crediting the shooter for the extra point before dividing by the total field goals attempted.
eFG% = (FGM + (0.5 * 3PM)) / FGA
Strategic Application
eFG% is the cornerstone of modern "Moreyball" analytics. It proved mathematically that a team shooting 35% from the 3-point line is generating a higher eFG% (52.5%) than a team shooting 50% on long 2-point jumpers (50.0%). This metric single-handedly revolutionized the spatial geometry of the modern basketball court.