Via The Book Blog , Bill James recently did a study on whether a "young" player's development has anything to do with their walk rate. Sadly, I am not a subscriber to Bill James Online, so I am unable to read the whole study and fully comment on it. What I do have are the two excerpts posted by Tango:
Anyway, I was wondering: does a low walk rate predict a failure to develop as a hitter? Because I can see it either way. I can see that a low walk rate for a young player could be an impediment to development, but I can also see how a low walk rate might be predictive of development, in this way: that the hitter who walks more, as a young player, can be seen as a more finished product, and therefore as a player who has less room to develop. There’s an extra door open for the undeveloped hitter.
This makes perfect sense to me. It's not necessarily how I personally evaluate young players or prospects, but it works. A young player who has a high OBP but doesn't have any power is pretty much finished in terms of his development. A low-OBP guy with a ton of power can always theoretically learn to take a walk on more occasions. Again, I don't have the meat of James' study so I'm not sure what he did, but he reached the following conclusion:
Essentially, there is no reason to believe that the walk rate plays any predictable role in the future development of a young player.
Now, since I didn't read the piece, I can't really comment much on it. I don't even know what James's definition of "future development" or "young player" is. I don't know if he's talking about young minor leaguers or young major leaguers.
However, I find that last part very interesting and it just didn't sound right to me. The first part makes sense, and I'd love to see the data James peruses to get to that conclusion, but I just can't pay for that right now.
Anyway, I'm not trying to debunk James's conclusion here, but it just got me thinking. The following little study I put together is far from scientific and has serious sample size issues. I took the 149 major leaguers who qualified for the batting title and sorted them by their 2009 wOBA. I wanted to see how the group's wOBA correlated with their minor league walk rate.
Now, I know this isn't very scientific at all; comparing people who are all in different stages of their career to their minor league numbers doesn't make perfect sense. Also, using just 149 players isn't nearly enough. If I were to thoroughly study this, I'd have to use many more players and many more years of data. I would like to, but I currently don't have the resources or time to embark on that right now.
A few other things to note about the sample I used. Since it was only players who qualified for the batting title, there is not a normal distribution. The league average wOBA in 2009 was .329 and this group had an average .353 wOBA. Only 38 of these players posted a wOBA below the league average.
Here's what the data on these 149 players told me:
The correlation coefficient came out to .313, which suggests a weak positive correlation. I wonder what the data would look like if I had used a bigger sample with a more normal distribution, but this is what I got.
Now, this is such a small sample that it can't confirm my biases that walks do matter for young players, but I still figured it would be interesting to take a look at. Also, out of all of the players in the top 50 wOBA, only five of them posted minor league walk rates under eight percent.
I find this to be a very interesting topic, as I find it hard to believe that a young player's walk rate doesn't suggest too much about a player's future performance. Maybe if I read James's entire study and saw his data, I'd buy into it. Until then, though, my bias that walk rate is important for young players remains.