Draftee ages: continued

By On October 14, 2011 · 4 Comments · In Prospects, Statistical Analysis

In my post yesterday, I described a very interesting study by Rany Jazayerli of Baseball Prospectus, which found that the youngest high school hitters in a draft class were more valuable relative to where they were drafted than the oldest high school hitters in the class.  The implication of these results was that teams don’t seem to adequately take draftee age into account when they are evaluating draft prospects, which made me curious about the Yankees’ evaluation of Cito Culver and Angelo Gumbs, both of whom were drafted at age 17 in 2010.

My main criticism of the initial study was that it only looked at the outliers: the oldest and youngest high school hitters drafted in the first 100 players, and I was curious to see if this effect held across multiple age categories.  Fortunately, in Part 2 of the study, Jazayerli did just that, dividing all the high school hitters in the study into 5 groups based on their age at the time of the draft, and compared the difference between actual and expected value produced by the players.

Players in the youngest category produced nearly 25 percent more value than one would expect given their draft position, and those in the second-youngest category produced over 11 percent in excess value.  The hitters in the middle category produced 7 percent more value than expected.  By contrast, the older hitters greatly underperformed relative to their draft positions, with the two oldest categories providing less than 70 percent of their expected value.  The size of the effect is pretty striking, along with the linear effect of age across the categories.

If you’re interested in the calculations behind the findings, feel free to check out the article, as they are laid out in a pretty clear fashion (this coming from someone who has taken statistics but is far from an expert).  It’s another must-read in my opinion, which sheds some light on potential areas in which major league teams could improve their ability to predict which draft prospects will be more successful.  Even a difference of only a few months can potentially be very significant according to the results of the study.

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4 Responses to Draftee ages: continued

  1. T.O. Chris says:
    October 14, 2011 at 8:52 pm

    So I assume this can be said for foreign free agent signings as well? In other words would it equate to giving out bigger bounces for younger players, and receiving greater value payout in return. Banuelos jumps to mind as someone signed quite young, as well as Montero.

    Reply
    • Eric Schultz says:
      October 15, 2011 at 2:11 am

      Quite possibly, though most legitimate prospects sign at 16, so there may not be much of an age difference for big-bonus signees.

      Reply
      • T.O. Chris says:
        October 15, 2011 at 2:19 am

        This is true. But in some situations such as players having to defect from say Cuba, or a player who lies about his age and has to sit out a year or two until he signs. These older players still get some fat bonuses. Teams seem to be inclined to give some of these guys who lie about age at times even bigger bonuses than before they were caught. Maybe in that situation it is better to move on from said player, and go after maybe less heralded younger players. Though I suppose since there is no draft order preventing you from snagging as many foreign born players as you want, the whole point may be moot anyway.

        Either way, very interesting study. I enjoyed both pieces Eric!

        Reply
        • Eric Schultz says:
          October 15, 2011 at 11:10 am

          It would definitely be interesting to look at international free agents to see if there were an age effect (with expected value determined by bonus size rather than draft slot). However, given that most good IFA’s sign at 16 unless there is an age/identity scandal, I imagine there wouldn’t be as much of an effect (though a few months could make a difference as this study showed).

          It was definitely an interesting study, and a topic I have always been wondering about, since the age difference between high school draftees can often be pretty significant. I’d be curious to see if there were a similar effect for high school pitchers as well.

          Reply

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