Crunch Time Revisited

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Earlier this year, I took a look at the Houston Rockets performance during crunch time compared to that of other NBA teams. The results were ugly. With 30 seconds left in games in which the Houston Rockets were down by five or less, the Rockets offensive rating was 37 points per 100 possessions. That’s just abysmal, but probably wasn’t very surprising for Rockets fans who had become used to throwing things at their TVs during close games.

At the end of February, I grabbed updated crunch time data. Now I’m finally getting off my ass to do something with those data. The chart above visualizes data from both times when data were collected.

What’s similar between the two time periods is that teams inexplicably still rely on heroball during crunch time (again, defined as late in games down by five points or less). I feel like coaches should have to write HEROBALL IS DUMB on the chalkboard Bart Simpson style. To reiterate, tomes of data all conclude that isolation is the least efficient offensive play, and common sense dictates that it becomes even less efficient if the opponent knows it’s coming. But, if you look at the chart, you’ll see that offensive ratings and assist ratios both decrease as games become tighter. I give up.

What’s different is that the Rockets went from being one of the worst crunch time teams in the league to being a somewhat average one. Their offensive rating with 30 seconds left while down by five or less rose to 85 (obviously we’re working with small sample sizes here). More importantly, at least for me, is that increase is coupled with an increase in assist ratio. That means the better offense is (probably) resulting from extra passes being made, and not simply because heroball shots that were previously rimming out are now falling. If the latter were the case, we would see the Rockets circle move straight up, indicating an increase in offense without any increase in assist ratio. Instead, we see it move up and to the right. Recent crunch time highlights of driving and kicking to open shooters (e.g., Harden to Beverley) come to mind.

In fact, that upper left quadrant is probably the most important one. Since assist ratio and offensive rating are closely intertwined (assists result in points by default), we would expect teams to trend upwards and to the right. The ones that truly heroball, and do so successfully, would be found in the upper left quadrant. These teams are offensively efficient but don’t pass. The only team that is consistently in this quadrant, in both time periods, is the OKC Thunder. If you’re going to heroball, you better be #35 on the Thunder, or else you’re just dumb.

On a slightly more flexible note, the data also show that a certain amount of individual shot-making ability is helpful during crunch time. The second most interesting quadrant is the bottom right. Teams in this quadrant have high assist ratios, but low offensive ratings. Basically, they only score if there’s an assist involved. Like the upper left quadrant, it’s pretty hard to make it into this quadrant, since, as stated before, assists automatically lead the points. It’s telling that the two teams who can’t get out of this quadrant are the Chicago Bulls and Minnesota Timberwolves. They are two teams who pass well but have either poor shooters or players who aren’t necessarily known for creating for themselves (yes, I put Kevin Love in this category). Someone like James Harden obviously can, and it looks like the Rockets as a team are learning how to utilize all his skills during crunch time, and not just his shooting.

About the author: Richard Li is an independent researcher and consultant. He likes numbers and pictures.

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