Friday, October 13, 2006
Run Estimator for Softball Leagues
I was given some softball league stats for a reader, which looked like this for BA/OBP/SLG:
.440/.500/.565
Basically, lots of singles and walks, and a few extra base hits sprinkled in. The data looks like it’s a 7-inning league, with an average of 12.4 runs scored per game.
When I ran it through BaseRuns, I got 9.1 runs per game, which is a hefty difference.
I’m also assuming no reached on error, as the data makes me believe that everything was either a hit, out, or sac.
In order for me to resolve to the runs scored, I had to double the “B” factor, which is a huge fudge.
That is, while a MLB team with these stats would score 44.5% of its runners who reach base, this softball league scores 61.6% of its runners.
With this new fudged version of BsR, here are the Linear Weights for this softball league:
BB: .62
1B: .81
2B: 1.16
3B: 1.59
HR: 1.48
out: -.84
Clearly, we have an issue here with the triples and HR, but we’ve already known that from the beginning.
Now, in this softball league, like I said, the OBP is .500. How often should the runner from 3B score? Let’s make it very exaggerated and say that every out is a sac fly. So, with 0 outs, the runner from 3B will ALWAYS score. Same with 1 out. With 2 outs, he’ll score half the time. So, the best we can hope for is, on a triple, the runner will score 83% of the time.
Seeing that 5% of the outs are K, and let’s assume that 5% of the other outs the runner on 3B stays put, and on the other 90% of the outs, the runner on 3B scores (still exaggerated), a guy hitting a triple will eventually score 82% of the time. Let’s stick with that figure.
Now, if that’s the case, how often will a guy getting on base via a double will score? Let’s just assume 75% of the time. Since we know that the team scored 668 runs, then we simply solve for “x”, the % of time a runner scores from 1B, and that is 59%.
So, the getting on value for a walk, single, or HBP is .59 runs. BsR estimates the total run value of a BB is .62, meaning the “moving over” value of a walk is only .03 runs.
The moving over value of the single is .22 runs, .41 runs for a double, .77 for a triple, and .48 for a HR. What is interesting about the run value of “moving runners over” for these (if you average out the triple and HR to .62) is that they are exactly what MLB has! That is, the “moving runners over” impact is just about independent of the run environment.
The biggest impact we have is outs, and anyone making an out is doing a really bad job.
Anyway, BaseRuns does a terrible job with the triples, and this should be addresses immediately.
Next time, I’ll use my basic-Markov run modeller (which I know I promised to release, and I will… I just haven’t spent the appropriate time to make it useable), to see what LWTS values we *should* be assigning. And we’ll also see if BaseRuns broke down because it doesn’t work at high run environments, or if it’s because the baserunning movements was based on MLB levels (say, 1B to 3B on a single is 33%). Ideally, it’s because of the latter, and therefore, the fudge I applied was totally acceptable, and serves to address this issue. If it’s not because of that, then we need to rethink BaseRuns.
Stay tuned…
I just got a note that the team reaches base on error 3 times a game, with about 2 baserunning outs per game, along with 1 WP per game. I’ll have to rework everything, since this will clearly impact what I’ve just done.