Numbers are everywhere. Some matter, some don't. Almost all of them need context. In fantasy baseball though many fall in love just with a players “fantasy” performance. How many homers or runs scored does he have? Are his ERA and WHIP great? In so doing, many neglect to pay attention to the underlying factors that really matter. What is the approach of the player. What does the totality of data say about the player. Is he over or under performing? That's the constant goal for me, to help people to answer that last question.
You may or may not be aware, but there are quite a few metrics out there that could help you to determine a hitters overall effectiveness. In this piece we will discuss a sabermetric measure which is used to gauge a hitters overall effectiveness, and that is Bases per Plate Appearance, or BPA.
WHY PLATE APPEARANCES?
There are a plethora of measures out there that can tell you how much power a guy has in his bat, how good a base runner he is or how many beers a guy could drink before passing out, but if they are so flipping complicated that you need to have a couple of degrees from MIT to understand them what’s the point? It's hard enough to get folks to read a 1,000 word article. I don't want to turn someone off in the second paragraph of said article, so I try to avoid presenting things that require calculators. Luckily for you, BPA is a simple idea that is pretty straightforward.
BPA is a measure which presents a way to quantify how many bases a hitter earns per Plate Appearance (PA). Notice that this metric focuses on plate appearances and not the more traditionally referred to idea of at-bats. The reason is that we are concerned with every time a hitter comes to the plate regardless of the outcome of the event, so BPA considers such occurrences as walks and hit-by-pitch, events that count in the PA column but not in the AB one (one of the reasons that batting average is limiting is that it only records at-bats and doesn't give credit to the other things that an offensive player accomplishes. This is why leagues that use batting average could very easily transition to on-base percentage if they are interested in rewarding the offensive skill of batters more accurately). To that end, here is the full formula for plate appearances:
Plate Appearances = AB + BB + HBP + SF + times reached on defensive interference
With that understanding of why BPA uses plate appearances instead of at-bats, let’s move on to BPA itself.
Here is the formula for BPA:
I told you it was simple right? BPA measures which batters are capable of generating the most bases when they come to the plate, it is really as simple as that. BPA Therefore would favor any hitter who has a high average, extra-base power and a discerning eye.