Goosing your Height

A fun post on reddit asked the question: “I hardly ever see a NBA player that is 6’2, is there a reason why?”

This asks two questions — first, is it actually true that there aren’t very many players that are 6’2″? Or is this just a recall bias? Second, if it’s true, why?

To verify the first question, I pulled all of the player heights from the current NBA rosters, and plotted the distribution of player heights in inches.

 heightsHist

What is interesting about this distribution is how weirdly unsmooth it is. There are three jumps that I have marked — between 5’11” and 6’0″, 6’2″ and 6’5″ and 6’6″. Height tends to be relatively bell-curved in its distribution (once you control for gender) and so these types of jumps are very bizarre. First, they suggest that the poster is absolutely correct in thinking it’s bizarre how few 6’2″ individuals he (or she) sees — there are far less than there should be. Second, many basketball players are skewing their heights upwards to 6 foot, 6’3, and 6’6. 

As for reasons why, I’m less sure. There is the easy answer that players tend to just inflate their heights — there’s no set measure on how do the measurement (shoes on or off?) and I don’t think the league particularly cares much. What is funny is the fact that someone cares enough to fake it. These sorts of habits probably begin in high school (I certainly remember saying I was six foot when I wasn’t quite there) and they just die hard.

Update: 

At the suggestion of a commentator on reddit, I pulled the pre-draft stats on height from DraftExpress. In the interest of speed, I just pulled the heights of everyone measured pre-draft, and plotted the distribution of heights.heightsDraftHist

 

In this case, we don’t see the same kinds of jumps — there is perhaps a little bit of funny stuff going on between 6 foot and 6’3, but that is likely more because of my bin choice (although I could be wrong). So this confirms our intuition that this is simply a reporting fact, not any underlying real selection factor. 

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