Front-court Defense, Height, and Age

Does height matter? The answer, to anyone who has followed the Houston Rockets closely this season, has to be yes. The Rockets have utilized the shortest front-court in the league, by a fair margin, this season, as depicted in the chart below:

From above, we see that the relationship between height and team defensive efficiency is not so clear, indicating that there are many other variables (team philosophy, experience) to be considered. The Houston Rockets, as poorly as they’ve defended of late, are actually not too far below league average (though note that the data for the chart above was from before the trade). Still, they have clearly slipped, and the absence of an interior shot-blocking presence has to be the considered the primary reason. But there are others:  many new players added to the team is a factor, as well as the Rockets playing more younger players.

Here is another look at this relationship, showing individual front-court players (who’ve played at least 500 minutes ).

“DEF on” is simply the team’s defensive efficiency with each player on the floor, and “DEF On/Off” is the team’s defensive efficiency with the player on the floor minus the efficiency with the player off the floor. Note that the lower either of these metrics are, the “better” the team defense is with that player (presumably, of course this is a bit of a simplification).


Conclusions? There is a very minimal correlation between increased height in the front-court and better defensive +/- stats, but really the only conclusion one can draw is that  (again) height is not a strong indicator of defensive impact. We see that there is actually a somewhat stronger relationship between increased age and defensive impact, which isn’t a surprise.

The problem here is that height is not necessarily a useful indicator of how much “interior presence” a player provides due to his length. What we can do is combine height and shot-blocking prowess into a single metric and see if there is a stronger relationship between that and defensive impact. We will explore this issue further in coming weeks.

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