from Amazon
Thursday, September 30, 2010
Using injuries for forecasting
Now here’s some new ground being broken:
As an example, let’s consider hitters who went to the disabled list with an injury to the lower arm (hand, wrist, or forearm). It’s widely accepted in baseball that wrist injuries have a lingering impact on a hitter’s ability to hit for power. This gives us 77 hitters to study, with 32,763 total plate appearances the following season.
Using the same method we used to look at Ichiro Suzuki yesterday, we can come up with an expected batting line for these hitters. As a group, weighted by playing time, they were expected to hit .266/.333/.427 the following year. Instead, they hit .270/.344/.439. So we can see that these hitters as a group tended to exceed their baseline forecasts.
It will be interesting to see how much is real (causation) and how much is best-fitting (correlation). But, definitely, this is one of those untapped areas. I have to believe that this will impact pitchers far more than non-pitchers. This will be pretty fun to watch develop.
And, this warms my open source heart:
So what we’ve done is taken a publicly accessible injury database, created by Josh Hermsmeyer of RotoBase, and worked on proofing it and improving it for incorporation into PECOTA. (Once we’ve finished updating the database, we will be releasing it at some point during the offseason, for other researchers to use.)