The Myth Of Fingerprints
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There are now three attempts at coaching analytics preserved in the musty archives of Hickory-High. These three “lineup optimization pieces,” blunt in method and vague in results, have still left a general sense of which coaches manage their rotations well. As with most statistical metrics, these methods offer quite a bit of information about the “what” but not so much about the “why.”
My three studies showed huge fluctuations between a coach’s numbers from season to season, and from their regular season numbers to the playoffs. I’ve been looking at these numbers for weeks now, expecting to find a pattern – success for coaches who are flexible, or inflexible; success for coaches who ride a particular group of players, or those who let nightly matchups guide their decision making. Perhaps sharper eyes than mine will eventually discern the edges of these scenarios, but I’ve really only found one thing. Small decisions, sometimes just a single choice, can have a huge effect on how rotations and a team’s success shake out.
The huge influence of tiny selections is particularly prevalent when it comes to the playoffs. Data comes from many sources and a coach needs to reconcile the different bits of information to make their choices. For their consideration is the success of particular players during the regular season against the entire league, a specific opponent, or a specific style of play. There is recent success or failure. Then there is the short-term data set of what is actually happening on the floor once the series begins. A coach’s ability to process and appropriately weight that information, quickly, is crucial.
Take the case of the Spurs’ Gregg Popovich. Popovich has obviously been extremely successful and has built a well deserved reputation as someone how manages his rotations well, making the most of his supporting cast. However, his lineup optimization numbers the past few seasons have not been impressive, particularly in the playoffs. This past season Gregg Popovich had a 0.784 correlation between the effectiveness of each five-man unit and the number of minutes he used that unit. In the playoffs that number dropped to -0.025.
Memphis peaked at the right time, causing problems for the Spurs that they didn’t encounter during the regular season. But the Spurs still had lineups that were more effective than others. The numbers show there wasn’t a connection between the effectiveness of those lineups and how often they played. I think one small decision, keeping DeJuan Blair‘s minutes down, was a big part of the problem.
Here are the six most used lineups from the Spurs’ playoff matchup with the Grizzlies.
[table id=33 /]
You’ll notice the Blair appears in none of those lineups. This is despite the fact that he spent most of the regular season as the starting power forward in a lineup (Tony Parker – Manu Ginobili – Richard Jefferson – Blair – Tim Duncan) that played 687 minutes together and finished the season with a Net Rating of +10.13. It’s not as if that combination struggled specifically against Memphis either. They lineup played 15.90 minutes together against the Grizzlies in the regular season and outscored them 42-26, for a Net Rating of +47.38. They also had an impressive OReb% of 41.7% against the Grizzlies front-line.
Despite their track record from the regular season, Popovich allotted all of 1.03 minutes for that group to play together over the course of their six playoffs games. Blair himself played a total of 50.33 minutes in the series, with the Spurs outscoring the Grizzlies 103-91 while he was on the floor.
Blair reportedly didn’t keep himself in shape throughout the season, exacerbating his issues on the defensive end. However, his monthly splits were reasonably consistent in terms of FG% and Reb/36, the areas he provides the most value. From where I’m sitting in my comfortable armchair, Popovich ignored a lot of evidence in making his decision. I’m assuming he saw a guy struggling to keep up physically and offer competition on the defensive end. He weighed that as more important than the fact that Blair was a key component in one of their most consistently successful lineups all season, had been successful against this specific opponent, and made a difference in the short time he was on the floor in the playoffs. Popovich obviously saw something different, and he’s certainly privy to more information and data than me, but the case seems pretty solid that cutting Blair’s minutes was one of the reasons their overall rotation wasn’t as effective as during the regular season.
We saw some similarly curious decisions from Phil Jackson this season. In the regular season he maneuvered his way to a correlation of 0.695 between the effectiveness of a unit and how many minutes they played. In the playoffs, that number fell to 0.475. As with Popovich we find a failure to adjust, but here it takes a different form. Cutting DeJuan Blair‘s minutes cost the Spurs. Jackson’s insistence on playing Andrew Bynum cost the Lakers.
Bynum played 134.16 minutes in their playoff series against the Mavericks, with the Lakers being outscored by 54 points in those minutes. Seeing as how their differential for the entire series was -58, I’d say those Bynum minutes were pretty important. Jackson used seven different combinations that featured Bynum at center, for at least three minutes against the Mavericks. Every single one of them was outscored. This was not the case during the regular season, where Bynum played 103 minutes against the Mavericks with the Lakers a +17 during that time. In their three regular season matchups, Jackson used 6 different lineups for at least three minutes with Bynum at center. Only one of those was outscored by the Mavericks.
I admit it’s an exercise to in ludicrousity to assume that I koew all the factors that informed each choice. I’m only describing the appearance of each decision-making process from the outside. It seemed that Popovich was focused on a mid-season slide, something that he saw outside the numbers, in limiting Blair’s minutes. Jackson seemed too focused on continuity and the success the Lakers had with Bynum against the Mavericks in the regular season.
I began this coaching analytics project hoping to find big themes. What I’ve found instead is a table of contents leading to a million tiny stories. If you’ve taken the time to find any of your own, the comment section is open.