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Monday, December 12, 2016

Small Sample Sizes

I love baseball stats. I'm the nerd that will fool around with Fangraph leaderboards in my free time. So much in the game is quantifiable that you can paint a pretty good picture of the best players in baseball by just looking at certain numbers.

If you are a frequent reader of sites like Fangraphs one of the main points they try to get across is to not fall for the dreaded small sample size. Every year a player has a monster April and someone will crown them the next best thing and sure enough by seasons end the overall numbers are pedestrian. People will bombard the writers with questions about someone and most responses center around not trusting April stats.

All this popped in my head when I found this Josh Harrison Pro Debut parallel.


The blurb on the back of the card mentions that Josh got a promotion because of his excellent eye.  Here are Harrison's walk rates as a member of the Pirates.

2011  1.5%
2012  3.6%
2013  2.1%
2014  4%
2015  4.2%
2016  3.4%

Obviously enough data exists now to show that plate patience is a weak point in his game. This is not meant to be a knock on Harrison as he is still a very valuable player. It just shows where my mind goes when I read about stats on back of a card. Also, if you are reading Josh, it is ok to take a pitch :)

Thanks for reading.

8 comments:

  1. I have the alternate John Harrison. Want it? Ha ha.

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    1. Ha. I like Harrison and wasn't trying to pick on him. Topps was correct in that he showed a nice eye to get promoted. I just wanted to talk about small sample sizes and that was a nice jumping off point.

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  2. Small Sample Sizes. Man, they can burn a fantasy baseball player, too.

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    1. Every year someone gets going in April and people declare him the next big thing.

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  3. Good catch. Topps needs to add you to their team.

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    1. Well, they were right....I just wanted to bring out that stats over that short period of time shows nothing about the player.

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  4. I agree generally, but I will add this: when a guy like Harrison isn't known for his plate discipline but shows ridiculously good discipline at a low-level minor league stop, that is often as good of an indicator as any that it might be time for a promotion. If the plate discipline holds up after that, then it can be a trend and a trait. As you said, though, Topps's ascribing Harrison with this trait based on 33 games in 2008 is slightly overboard.

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    1. I agree. Harrison was a college player so he was probably advanced for the low level minor leagues. His true self came out in the upper levels and the big leagues.

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