Welcome to Get to Know a Stat! Once a Week (or so) I intend to take an advanced baseball statistic and present it to you in a way that’s understandable.
We’ve spent the last few Get To Know A Stat posts discussing pitching stats. This week we’re going to look at a few batting stats, some of which will make appearances later this week. Nothing too complicated, but hopefully they can help us answer some questions we might have about batters. Let’s start with power.
Traditionally, the basic statistic is slugging. Slugging (SLG) is a measure of total bases divided by at bats. Total bases counts the number hits a player gets, but weighs the extra base hits heavier than regular base hits. Specifically its 1B + (2 X 2B) + (3 X 3B) + (4 X HRs). Batting Average doesn’t increase if players hit doubles, triples and home runs-but the Slugging will. Like ERA and Batting Average, I think it works okay as a big picture stat, but it still takes singles into account-which isn’t really a measure of power.
ISO or Isolated Power takes singles out of the equation for power. The easy way to do it is to subtract a player’s batting average from his slugging percentage. This effectively leaves you with a new numerator of 2B + (2 X 3B) + (3 X HR). For me, looking at ISO is a little less unwieldy than looking at slugging. It brings the number back down into the 1-200 range makes it easier for me to read. Plus, it takes out hitters who are just good hitters, but aren’t powerful hitters (not that there is anything wrong with being a good, but not powerful hitter).
Both of these stats, however, can overvalue the power of a fast base runner. If you’ve got a guy who routinely turns singles into doubles, etc., that is going to skew the numbers a bit. Indeed, you can hit it as hard as you want, but a triple is always going to require a little luck and a lot of speed. Still, over a season (and a career) speed won’t hold up as much as power will. Guys who get those extra bases by being fast will fade a little quicker than the big hitters.
We’ve talked about BABIP in a roundabout way before with Roger Bernadina. It measures not the full batting average, but just the Batting Average on Balls In Play (BABIP). So rather than count everything, the stat takes out things that cannot be fielded. This average only keeps track of what happens when a batter hits the ball in the field of play. This video helps explain it well:
but I will explain it anyway. Basically an average BABIP is about .300-or 30% of balls in play go for a hit. A substantially higher or lower value indicates a player who is either very lucky or unlucky. A batter with a high BABIP is “hittin’ ’em where they ain’t.” A pitcher with a high BABIP is not getting help from his defense. A batter with a low BABIP may be hitting them hard right at a guy. The pitcher with a low BABIP is using his defenders well. Or whatever the narrative is that particular day.
The point is you can use BABIP to try to identify pitchers and hitters whose luck (or unluck) is due to run up. Generally, you’d expect BABIPs in the 340s (or 260s) to start to even out. This isn’t always the case-a batter who is good at making solid contact may well run a higher BABIP average than .300. As with any stat, take it with a grain of salt.
Questions and Comments welcome below.