The Spurs are firmly below .500 and are outside of the playoff picture at the moment. In terms of wins and losses, they seem to be a pretty bad team. But there is a number that suggests they might be better than their record indicates: margin of victory.
For those who aren’t familiar with margin of victory, it’s a very simple stat to calculate, as it’s just points scored minus points allowed. Despite that simplicity, margin of victory is used in predictive models often, in one way or another, because it helps estimate who is as good as their record suggests and who isn’t. Good teams not only beat bad ones, but they blow them out regularly. Bad teams might scratch their way into a few wins, but they’ll rarely dominate.
How the Spurs fare in the stat is really interesting. San Antonio has the 12th best record in the West, but the eighth best margin of victory, The 12-18 Spurs rank better than the 16-16 Lakers. They are closer to the top 10 in the league in the category than they are to the the Portland Trail Blazers. By Pythagorean wins, a more complex stat that uses margin of victory, they are a .500 team. It’s not completely surprising, since the Spurs kept a lot of games close earlier in the year, but couldn’t close them out, but it does show that perhaps this team could be a serious playoff contender with a bit more luck and consistency.
Working in the Spurs favor is a very top-heavy West. A simple look at the standings provides a good idea of just how stacked the conference is at the top, and margin of victory confirms it. The Warriors, Suns and Jazz are on another level, leading the league both in record and point differential. The next five teams below them, however, are from the East, and the only other West team in the top 10 are the Grizzlies, which caught fire with Ja Morant out. The Clippers, Nuggets and Mavericks are all bunched up together slightly above the Spurs, and the Lakers Timberwolves and Mavericks are actually under them in margin of victory. The Trail Blazers and Kings, currently ahead of the Spurs in the standings, have awful point differentials.
Normally in the West there are six or seven teams that are clear playoff locks, but at this point, at least going by margin of victory, we don’t seem to have many that fit the bill. Last season, for example, there were nine West teams in the top 15, all with strong point differentials, and they all made it at least to the play-in. This year there are just six, and two of those have a margin of victory that is merely adequate compared to past playoff teams. It seems like unlike other years, the conference is wide open outside of the top four, and with the Thunder and Rockets tanking, 13 teams will fight for eight places, accounting for the two play-in slots. Among them, the Spurs seem well-positioned to make a run, if they can turn some close losses into wins.
The main reason to remain skeptical of how meaningful margin of victory is in this and every other case this season is health. Not only have the Spurs been relatively lucky in terms of player games missed but have also faced severely depleted teams multiple times. In the vast majority of their 12 wins, their opponents were missing several rotation players. Some of the names that were fortuitously out when facing San Antonio include stars like Jrue Holiday and Damian Lillard, as well as a bunch of other standouts who are expected to be ready to go later in the season like Zion Williamson, Klay Thompson and Jamal Murray. There were absences in their close losses, too. Would the Spurs have this margin of victory if they had gotten unlucky with injuries or faced opponents at full strength? It’s hard to say. Would other teams have better point differentials if they had been as healthy as the Spurs? Probably.
The other problem is that while normally margin of victory tends to be a good predictor of record, there are some outliers. Over the past 10 years, teams that ranked in the top eight in their conferences in margin of victory got to the playoffs most of the time, but there were some cases that show that ultimately, actual wins are all that matters. For example, the 2015/16 Jazz ranked 10th in the entire league and fifth among West teams in margin of victory but had a worse record than four teams that ranked below them in point differential, including the 20th ranked Grizzlies. Something remarkably similar happened in the 2016/17 season to the Miami Heat, which also ranked 10th in the league and fifth in their conference and were edged by four teams below them in margin of victory, including the 19th ranked Hawks.
It’s safe to say that margin of victory, or net rating if you prefer its close relative, are not flawless predictors of actual record and that projecting current trends to hold, especially in such a strange season, is a recipe for bad analysis. A lot could be different 20 games from now and even if things stay the same, that doesn’t mean the Spurs will actually make the playoffs.
Even so, it’s always good to look at things other than the standings if the point is to understand how good a team actually is. Both by watching them let winnable games slip away and by taking a look at their point differential, it’s fair to say that the Spurs could easily have a couple more Ws under their belt.
Hopefully now that they’ve learned how to close better they’ll also figure out how to remain focused after big wins, so that their record and point differential start to match, in a good way.