We have seen a trend over the last four drafts that has been significantly different from the previous regime. Jeff Luhnow likes hitters with good plate discipline. It's common knowledge at this point. Anthony has done a lot of work the last few years identifying his "Fifty Very Luhnow Hitters". However, it hasn't truly been quantified the difference in philosophy of the scouting under Luhnow versus under former GM Ed Wade.
Bill James truly changed the way how many looked at baseball. Billy Beane brought that to the forefront by applying the progressive statistical analysis to a whole new level. We now look at BB/SO ratios and OBP as common place in player evaluation, years ago we did not. When I first started reading this very site, I did not. It's simple logic that walks increase the rate of getting on-base. And even still, the attribute of walk rates and strikeout rates tend to get overlooked in the scouting process to an extent.
Jeff Luhnow doesn't.
Under Ed Wade, tools reigned supreme and often times many of the prospects acquired during his tenure struggled to get on-base due to poor plate discipline.
The purpose of my research was to quantify the BB/SO ratios, batting averages, and on-base percentages of the Astros drafts from 2008 to 2014. We will compare the drafts under Luhnow and the drafts under Wade. I will also put the percentage of draftees that are position players have topped out at each level.
Ed Wade Drafts
Jeff Luhnow Drafts
There's really not much of a difference between the batting averages between the draftees in the two GM's tenure, but there is quite a large difference every where else. Nearly two-hundred point separate them in BB/SO ratio. Ratios are not directly proportionate rate stats like OBP, however it does illustrate that drawing a walk in important to this front office. What it does correlate to is a twenty-four point increase the OBP between the two groups.
Remember these have a huge bias toward minor league data as there are only a few players in the sample that have any major league experience. But, if you consider that a .320 OBP is considered roughly average (50) in the major leagues and a .340 is above-average (60), it would be at least a full grade upgrade in the plate discipline skills.
Now take a look at the distribution for each individual drafts. Notice that the four under Ed Wade have a lot of players topping out in A-ball and lower.
Over 2/3 of Ed Wade's picks didn't make it out of the low minors. Sure, there are a handful of guys remaining in the minors from those drafts that could make gradual improvements to those numbers, but the window is closing.
Now for Jeff Luhnow's. Luhnow's have had significantly less time to develop.
I honestly shouldn't even include the 2014 draft. But look at how 2012 and 2013 already have had a larger percentage of drafted hitters make it past Quad Cities. Better than every single one of Ed Wade's drafts.
Luhnow hasn't had a single draftee make it to the majors with the Astros. However, with 24% of the 2012 draft being in AAA and another 28% in AA, the time is soon.
There is also one thing to consider however. The coaches and player development people under Luhnow probably have a bias toward those Luhnow's draft picks. But, there is a correlation in better success among the players who have higher OBP's.
Man that 2012 draft looks good.