JA Scores - Explained

You will see the “JA Scores” scattered throughout the daily notes, the dashboard, and my tweets. I wanted to just quickly write this post to explain what that is so I can refer people to it when they ask.

JA are just my initials, I didn’t find this endeavor worthy enough of its own name - so that’s what it got.

Every pitch thrown generates positive or negative points for both the hitter and pitcher. I made up the scoring system, and it’s detailed below.

I am just trying to isolate how each player has performed at the pitch-level. It’s not a perfect scoring system, and I’m not going to claim that it’s super predictive of the future or anything - but it’s a decent way to put one number on player performance.

A lot of the scoring is based on the launch_speed_angle categorization that Baseball Savant does. That classifies all batted balls into one of six categories, here’s a quick overview of those six.

#6 - Barrels

These are the most well-struck balls. They are all over 97.5 miles per hour at specific angle ranges, and that angle range widens as the velocity goes up. About 50% of them go for homers, and another 20-25% of them go for doubles. The rest are mostly fly-outs.

Visualized:

#5 Solid Contact

These are the batted balls that just miss being barrels. They very rarely go for homers, and they are often flyouts, but there are a lot of doubles in there too.

#4 Flares

These are line drives that aren’t hit hard enough or at the angle to make them a solid or a barrel.

#3 Under

Weaker fly balls

#2 Topped

Ground balls

#1 Weak

These are balls hit below 60 miles per hour. Bunts included.

The issue we have is that hitters mostly dictate this. A hitter’s barrel rate is pretty steady year-to-year, that is not true with a pitcher’s barrel rate allowed.

The ones pitchers do control are topped and unders, since those are basically just ground balls vs. fly balls - and we know that a pitcher’s pitch mix and locations have a lot to do with that. But we shouldn’t punish pitchers too badly for giving up a barrel, because there’s not a ton they can do to control that - and you’ll see that considered in the scoring system.

The long and short of this is that we want pitchers who earn strikes and do not allow contact (and especially don’t allow hard contact, although it’s tougher for them to really control that), and we want hitters that don’t strike out and hit the ball well when they’re putting it into play.

The full scoring system is below, but again this isn’t really my main concern. I’m not going into the lab to refine and perfect this, and I’m not really trying to hold these scores up as if they’re one of the great things I provide - because they’re just not, it’s kind of just more for fun and for quick player ranking.

Pitching

Whiff = 4 points
Called strike = 2.5 points
Strikeout = 1.5 points
Walk = -5 points
Ball In Play = -1.5 points
Barrel allowed = -4 points
Solid allowed = -2.5 points
Flare = -1.5 points
Under = 1.5 points
Topped = 3 points
Weak = 4 points

Hitters

Whiff = -4 points
Taken strike = -2 points
Ball In Play = 3 points
Strikeout = -2 points
Walk = 3 points
Homer = 6 points
Barrel = 13 points
Solid = 8.5 points
Flare = 4 points
Under = -3 points
Topped = -6 points
Hard hit ball = 1.5 points