I don't think this is subscriber info, so I'll post the whole thing instead of abridging.  Originally tacked it into Prospect #37 diary, but  then felt it had enough tranferrable value to hopefully spark some larger discussion, especially in regards to other prospects:

From the Dec 19 chat at BP:

David (Sonoma State University): Is Clayton Kershaw REALLY that good? Why aren't the Dodgers more willing to trade him considering that they have Scott Elbert?

Nate Silver: Clay did a bunch of work on the pitcher DTs this winter -- I mean, some really thorough, painstaking work -- and one thing he found is that the difficulty curve for minor league pitchers is much steeper that we'd previously believed. So to the extent that Kershaw is a top prospect, it's at this stage more a scouting thing than a numbers thing -- his high walk rates are almost as much of a minus as his high strikeout rates are a plus. He's still an excellent prospect, but he's leaps and bounds behind the Clay Buchholz class of pitchers.

 
I found this interesting for four reasons:

1) Back when we were debating Kershaw, there were a few in here that vehemently claimed his walks prevented them from  placing him too high.  FWIW, Silver/PECOTA agree, though I was really surprised to see him say that the walks almost COMPLETELY negated the high K rates, when predicting success;  I'm pretty sure Artie was one of the guys leading that critique of Kershaw....

2)In his answer, Silver states flatly that Kershaw's distance from the majors (and walk rate) place him far behind Buchholz (for example) as a prospect.  This doesn't surprise me in terms of risk/reward. but it DOES surprise me in terms of upside.  Basically, that walk rate is a real problem, and until Kershaw fixes it, it affects not only his chances of reaches his "ceiling", but also the height of that ceiling in the first place.  

3) This is not just applicable to Kershaw - this is a transferrable issue, as we have other prospects coming up in the community poll that this very much applies to - Adenhart jumps immediately to mind.

4) While I am mentioning Artie, one of the things I've noticed him saying a lot this "season" is that he's giving some older pitching prospects a bit of EXTRA credit, just due to the fact that they're closer and are maybe a little more  projectable as _survivors_of the injury nexus.  I'm wondering if this age things also plays into PECOTA/Davenport's predictions, in the sense that perhaps there's not much credit given for accomplishment at a young ARL IF the pitcher is really young.

It's interesting that this view on Kershaw comes from a stathead stance, given that the stathead element of the public tends to really like Kershaw.  

Do you guys buy it?  Is Kershaw's ceiling really much lower Buchholz's - even after ignoring risk? Do his walks really hurt him that much?  

And, who else coming up might this apply to?  Adenhart, Lofgren, Elbert, ?????