The system, called KATOH, attempts to use minor league statistics to project how likely young players/prospects are to provide a certain level of value by the time they are 28. It’s an interesting analysis, so long as you understand how difficult and imprecise translating minor league stats to Major League performance can be.
Caveats aplenty, but one really, really, really notable thing his analysis found, as he revealed in the FanGraphs interview: walk rates in the lower minors have almost no predictive value with respect to future Major League success. Strikeout rates, however, are much more predictive at lower levels (they become equally predictive with walk rates by the time the player reaches AAA).
In other words – *according to this model* – if you see a guy in rookie ball or short-season Low-A or even full-season Low-A with a huge walk rate and a huge strikeout rate, you should be worried. A low walk rate and a low strikeout rate? Encouraged. A high walk rate and a low strikeout rate at those lower levels? Still encouraged, but mostly because of the strikeout part. If you see a guy in AA or AAA with a low walk rate and a high strikeout rate, you should be very concerned. But if the walk rate is really high at AA/AAA, you can still be encouraged, even if the strikeout rate is also very high.
This kind of analysis suggests things like: being encouraged about Albert Almora’s lower minors performance, being discouraged about Javy Baez’s performance throughout, being encouraged about Jorge Soler’s performance throughout, and being very encouraged about Kris Bryant’s performance in 2014. That’s all extremely shorthand, but you get the gist.
We’ve known for a good while now that, setting aside everything else, minor league walk rates and strikeout rates can be instructive as to future performance because they suggest certain foundational abilities (or lack thereof) that are built upon as players climb the ladder (or exposed by better pitching). But this adds a new layer of understanding – or at least suggests it – by specifying at what points in development the walk rate and strikeout right might matter most, and in what relative relationship to each other. Pretty interesting stuff.