Since I coded historical Bill James Pitcher Rankings, I started thinking about coding something similar for batters. I wanted to keep it similar to the pitcher rankings, so I needed to develop a game score for batters. Like with the pitchers, I concentrated on starters only. Remember, this is not a way to evaluate the best career, or even the best season. It’s a way of saying, at this moment in time, who is the best starting hitter.

Like pitching game scores, I start with a value of 50. The batter then can earn the following positive points:

• A hit is worth five points.
• Add three more for a double.
• Add six more for a triple.
• Add nine more for a home run. The value for hits are proportional to the long term linear weights for these types of hits.
• A walk or hit by pitch is worth three points. I include IBB, as great hitters like Barry Bonds tend to get walked intentionally. I’m using the IBB as a bonus for a sign of greatness.
• One point for each RBI. This just tries to separate batters a little more. A two for four with two RBI looks better than a two for four with no RBI.

Playing time in the game can be a positive or a negative.

• If a batter comes to the plate at least four times, he receives a point for each plate appearance.
• If a batters comes to the plate less than four times in a game, he loses five points for each missed PA. So if a player comes up three times, he loses five points. This is to help drive down the scores of pitchers who bat, but also will affect hitters batting low in the order who are less likely to bat often.

Batters receive negative points for the following:

• Outs. This is a bit complicated. I define outs as (AB – Hits) + SF + SH. If the number of outs is less than or equal to three, then subtract three for the (AB-Hits), two for the SH, and one for the SF. If outs is greater than or equal to four, subtract nine for the first three outs, 10 for each additional out, and the same penalty for sac hits and sac flies as before.
• Subtract one point for a strikeout.
• Subtract one point for a GDP.

The idea is that a 1 for 4 with a single and nothing else should give a player a game score around 50. No one is going to be crazy about a hitter who goes 1 for 4 every day, despite his beating Dimaggio’s hit streak. He gets four points for his four PA, five more for the single, and loses nine points for the outs. He comes in exactly at 50. If he goes 1 for 5, he gets ten positive points and 19 negative points for a 41. An 0 for 6 takes a hitter down 33 points (6 for the PA, -39 for the outs).

A really great game, like a batter hitting four home runs, puts him well over 100. Those games will be rare. A four for four cycle is worth at least a 93. A rare 0 for 7 will take a hitter into single digits, especially if there are strikeouts.

I use the same park effects as for pitchers, except in the opposite direction. I use the same inactivity factors, except I start the penalties after three days rather than six. It’s very unusual for a good hitter to miss four days in a row. Like pitchers, I also use post season data.

Here are the rankings as of the morning of 4/26/2012. I don’t think anyone would argue that Matt Kemp is the best hitter in baseball right now. Pablo Sandoval and Chase Headley actually get nice boosts due to the low run environment in which they play. David Freese gets a nice carry over from the post season. Corey Hart has been on fire since the middle of 2011.

I’d love to hear your thoughts and criticisms. If people like this, I’ll work on posting it every day, and work it back through history so you can see how they change.