. Is this valid?

Compared Saved MP rate in year N vs. year N+1

There should be a correlation between these numbers.

1232 catcher-years with ≥ 700 opps in consecutive years, r = 0.42

223 catcher-years also changed franchises, r = 0.40

What does this mean?

For same time period considered park-adjusted batting average relative to league

4772 batter-years showed a correlation year-over-year, r = 0.45

MPsaved is as telling of a catcher's ability to block pitches as batting average is to a hitter's ability to get hits