Statcast: BABIP; OPS+; ISO

General Baseball

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Now that I’ve covered all the bases in the area of basic stats, it’s time to get into some more advanced stats. In this post, I’m focusing on four stats that are used to measure hitters.

Batting Average on Balls in Play (BABIP)

BABIP does exactly what it sounds like it should do: measure a player’s Batting Average on Balls in Play. BABIP removes all outcomes not affected by the opposing defense, mainly strikeouts and home runs. The formula is (H – HR) / (AB – HR – K – SF).

If a player went 1-5 in a game with a home run and a strikeout, his BA would be .200 but his BABIP would be .333 because the strikeout and homer were removed from the picture.

One way BABIP is used is to determine why a player is struggling. For example, if a player was hitting .250 and his BABIP showed .400, the conclusion would be that he strikes out a lot because he gets lots of hits when he puts the ball in play. On the other hand, if the player’s BABIP was .150, the conclusion would be that he’s hitting the ball to fielders. This is known as hitting into bad luck.

On-Base Plus Slugging Plus (OPS+)

OPS+ is designed to compare players across different eras. This is important because a player with a .750 OPS in the dead ball era might have been considered good, while a player with that OPS now would be considered poor.

OPS+ takes a player’s OPS adjusts it for ballparks, divides it by the league average for the year and multiplies it by 100. In OPS+ 100 is considered league average and 150 is 50% better than league average. The formula is (OPS/league OPS, adjusted for park factors) x 100. As you can see, this is a complicated stat and it is better to just look this one up online.

This stat is so great because provides a fair comparison between eras. Because it compares a player to the rest of the league, you can see how much better than his league a player in the ’60s was, then compare him to how much better than his league a player this year was.

Isolated Power (ISO)

Isolated Power attempts to measure the raw power of a hitter by measuring a player’s extra-base hits. Although it may seem confusing, the formula is actually pretty simple. Extra Bases / AB. As you can see, singles don’t count toward ISO.

If a player goes 1-4 with a single, his ISO is 0. If a player goes 1-4 with a double, his ISO is .250.

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