While watching games, I’m simultaneously intrigued by and skeptical of stats that announce that player X does Y at Z effectiveness when his team wins, and not when his team loses. It’s a nice thought, that one player’s specific behavior might indicate, or even predict, his entire team’s outcome, but the choices of data are mostly arbitrary.

To make this exercise a little more robust and interesting, I decided to inject some statistical steroids into the traditional analysis. Below is a graph that shows the difference in five indicators (assist ratio, defensive rating, offensive rating, true shooting percentage, and usage percentage) between team wins and losses of all nine of the Houston Rockets regular rotational players (click for a full-sized interactive version).

First, the boring technical explanation. Offensive and defensive ratings are points per 100 possessions. Assist ratio is the number of assists and individual player has per 100 possessions. True shooting percentage is a field goal rate that considers three-point shooting percentage and free throw percentage. Usage rate is an indication of how much of a team’s posessions is “used” by a certain player (i.e., how many times a player shoots, goes to the line, etc.).

On the x-axis are players, excluding Asik due to lack of sample size. Leading each cluster of players is the Houston Rockets as a whole (the red bar). Also on the x-axis are the players’ performance in five statistical categories. The y-axis shows the players’ percentage change in those five aforementioned categories from games that the team wins to games that the team loses. Please note this is the percentage change in the statistic, not the nominal change. So if a player goes from 10 of something when the team wins to 9 of something when the team loses, his difference in this chart is -10%, not -1.

Finally, a warning about how to interpret these results. These data DO NOT show causality. In fact, the directionality of these data is completely unknown. Basically, we don’t know if the Houston Rockets start losing once Dwight Howard is featured more, or if Dwight Howard is featured more once the Houston Rockets start losing. Either scenario is equally plausible for each indicator.

Onto some quick hitting observations.

- Francisco Garcia appears to be the most offensively volatile but defensively consistent player. The difference in his offensive rating and TS%, especially his TS%, is the greatest on the team, while the difference in his defensive rating is the smallest.
- The point guards actually have more assists per possession in losses than in wins.
- The team’s “stars” and Casspi (?) see an uptick in usage during the team’s losses.

My opinion is that the final two bullet points indicate that there is a relationship between losing games and deferring to a few players. Regardless of what happens first, in games that the Houston Rockets lose, certain players pass more and certain players shoot more. Instead of trying to run an offense, players begin heroballing, thinking that it’s their responsibility to ignite a comeback. That’s usually a recipe that leads to bad results, barring extremely efficient performances from those privileged few. Perhaps sticking with the offense at hand, understanding that lumps will always be encountered, would be a more sustainable and effective solution.

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Total comments:7As redfaithful says, the spikes in PG Assist Rate are interesting and probably worth of further investigation. It seems like there could be a lot of possible explanations for this - could there be a correlation with injuries, for example? I could imagine with one of Beverley/Lin out, the other would be forced to play more and that might have far-reaching consequences for statistics like this. Would love to see a follow-up exploring the PG correlation, anyway.

ST

Sure a coach will probably ride their best players when the team is down but the fact that those players are seeing such a large decrease in efficiency and TS% makes me think that they need to share the ball a little bit more. It's a similar idea to the "line of awesome" in the "selfishness" analysis that Richard did. I agree with the article's assessment. The simultaneous uptick in usage rate and larger drop in offensive efficiency / TS% of certain players during losses is likely due to certain players taking it upon themselves to bring the team back into the game, heroballing, and actually performing worse. Impressively, Casspi has both a lower change in TS% than other players while simultaneously increasing his usage rate. Lin has the lowest change in efficiency and TS% but nevertheless has a large decrease in usage rate. Of course, it is unclear from the data whether his efficiency is high because he has a low usage rate or whether he really ought be used more. Nevertheless, one of Jeremy's strengths is his ability to create his own shot so, if anything, I would expect his usage rate to increase when the team is looking for a spark.

Btw, thanks to Richard for the stats and inciteful analysis. I'm a fan!

Absolutely true. Coaches will ride their best players down the stretch of close games. So how do you interpret Jones and Howard sitting on the bench in the forth quarter in the win against the Griz? Was McHale riding the hot hand, functioning from some sort of NBA mavens intuition? I found his decision to be somewhat startling.

Thusly, if the Rockets end up losing it's probably because their studs performed below average in the 4th quarter as pretty much is the case with any team in most cases.

Thanks for the feedback. I've cleaned it up a little bit. Is it more clear now?

A fascinating piece. Correlation is not causation. But I do think you need to clear up the meaning of the Y axis. I have read your post several times and I still do not understand it.

Assuming I got it correctly, the most interesting part is the assist ratio change. In losses PGs have relatively more assists and the interior players has less. It could be that in wins many times the ball gets inside to the big men with the defense collapsing on them, resulting in easy inside-out assists. When this is taken by the defense our offense is less efficient and the chances to loose increase.