ISO (Isolated Power)
Isolated power measures raw extra-base power by subtracting batting average from slugging percentage. What’s left is pure extra-base production — the gap between hitting singles and hitting for power.
A player with a .280 AVG and .530 SLG has a .250 ISO, meaning they’re generating a lot of extra bases beyond their singles. A .280 AVG with a .350 SLG gives a .070 ISO — almost all singles, very little power.
ISO is useful because it separates power from contact ability. Two players can have the same slugging percentage but very different ISOs if one has a higher batting average. It tells you whether a hitter’s slugging comes from power (high ISO) or simply from getting a lot of hits (low ISO).
What is a good ISO?
ISO reflects the power component that wOBA captures through its extra-base hit weights. High ISO players tend to have strong NUT Scores because their extra-base hits are worth more runs.
How NUT Score works →