If pitch framing is a repeatable skill then why are the numbers so variable for the high value catchers from year to year?
I haven't dug in too far yet, but I can think of three potential answers:
1) What counts as "so variable"? From 2007 to present, Joe Mauer's batting averages were:
.293, .328, .365, .327, .287, .319, .324
From 2007 to present, Mike Pelfrey's ERAs were:
5.57, 3.72, 5.03, 3.66, 4.74, 2.29, 5.19
Those all look pretty variable, but I don't doubt batting average and ERA are repeatable skills. How does pitch framing's variability compare to the typical stat?
2) We'd have to look at the sample sizes for each of the players in each year. Anyone who's a back-up or anyone who spent part of the year injured is going to have more variability because they caught fewer games--whether it's a counting stat (Total Framing Runs) or rate stat (Framing Runs per 7,000 Chances). Counting stats are obviously driven by playing time, but the rate stat's less accurate, too, if the sample's not large enough. How does consistency compare to annual sample size?
3) Some if it could just come down to seasonal opportunity. When I think about the year-to-year variability in defensive stats, I always think of any given center fielder and the number of chances he has every year to rob a home run. Some years you're just served up more opportunities. How many borderline calls are we looking at in a given year?
Again, without digging into the study yet, I think these are ranked in order of their impact--#3 the least, because even if borderline pitches aren't particularly common, catchers are seeing so many
pitches every year that I'd think, given a season of playing time, you'd have a good sample size. #1 first because it does
look to me like the same names keep showing up at the top and bottom each year.
Edited by Wookiee of the Year, 03 March 2014 - 06:45 PM.