Isolated power

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.

$ISO=SLG-AVG$

$=\frac{{T}{B}-H}{AB}$

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

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

$=\frac{({2}{B})+(2\times {3}{B})+(3\times {H}{R})}{AB}$

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.

See also

• PECOTA

References

• Baseball Prospectus Glossary
• Baseball Simple : Isolated Power (ISO) Calculator
• FanGraphs Sabermetrics Library