ISO, or Isolated Power is just that; a way of isolating a player’s power hits. It’s a pretty simple statistic which is calculated by taking a players AVG and subtracting it from his SLG%. Essentially this equation removes singles from the players SLG% and leaves you with his ISO.
Meet the Metrics: ISO
The name can be pretty deceiving because ISO isn’t an accurate measure of power. A player with plus speed, such as our own Jose Reyes, can maintain a respectable ISO due to his ability to turn long singles into doubles and doubles into triples. Therefore I would tend to look at it more as “extra base ability” as opposed to “power”.
ISO certainly isn’t a perfect stat, but it has it’s uses. My main beef with ISO is that it carries with it the same problems as SLG%. Both statistics fail to differentiate between a double and a triple or a HR. We all know those hits are not equal. Also as with most statistics, ISO isn’t something you want to judge on a small sample size.