In baseball, isolated power or ISO is a sabermetric computation used to measure a batter's raw power. One formula is slugging percentage minus batting average.

${\displaystyle ISO=SLG-AVG}$

${\displaystyle ={\frac ((\mathit {TB))-H}{AB))}$

${\displaystyle ={\frac {({\mathit {1B)))+(2\times {\mathit {2B)))+(3\times {\mathit {3B)))+(4\times {\mathit {HR)))}{AB))-{\frac {H}{AB))}$

${\displaystyle ={\frac {({\mathit {1B)))+(2\times {\mathit {2B)))+(3\times {\mathit {3B)))+(4\times {\mathit {HR)))-({\mathit {1B))+{\mathit {2B))+{\mathit {3B))+{\mathit {HR)))}{AB))}$

${\displaystyle ={\frac {({\mathit {2B)))+(2\times {\mathit {3B)))+(3\times {\mathit {HR)))}{AB))}$

The final result measures how many extra bases a player averages per at bat. A player who hits only singles would thus have an ISO of 0. The maximum ISO is 3.000, and can only be attained by hitting a home run in every at-bat.

The term "isolated power" was coined by Bill James, but the concept dates back to Branch Rickey and his statistician Allan Roth.^[1]