Analyzing NBA Point Differential: Which Teams Should Be Better?

Point differential is more predictive than win percentage. What teams are better or worse than their records say?

Sometimes simple win-loss records can be misleading. Although we at numberFire like to crunch as many numbers as possible, sports are not exact sciences -- sometimes teams just get lucky or unlucky.

For this reason, we have learned that point differential is much more predictive than winning percentage. When so many close games come down to final possessions, many times the winner is just the team that either had the ball last or hit a tough shot. That’s nice and can be useful and predictive, but oftentimes it’s not.

Since point differential gives us a better idea of how teams will perform in the future than their current win-loss record, let’s look at how teams are faring in that regard so far. In the table below, I’ve compiled each team’s winning percentage and league rank and each team’s point differential and league rank. By simply contrasting them, we can get an idea of which teams are better and worse than their actual record. The last column is their ranking difference –- the Mavs rank 10th in winning percentage but 3rd in point differential. Thus, we can guess that they’re probably better than their current 16-7 record indicates.

It seems pretty obvious that the Thunder are actually better than their current 8-13 record, but remember that this data hasn't really been affected that much by Russell Westbrook and Kevin Durant's return. When you combine that knowledge with the fact that they now have two top-10 players again, the Thunder are going to majorly progress upwards soon.

The Raptors might be a bit of a surprise here, as their point differential indicates that they should be better than their already best-in-the-East 16-6 record. It’s hard to say whether this is due to going 3-3 since the injury of DeMar DeRozan or whether it’s true despite the injury. They have an easy schedule over the next two weeks, playing the Pacers, Knicks, Magic, Nets, Pistons, and Knicks. We probably won’t know until DeRozan returns and they play other healthy teams where they stand.

The Golden State Warriors are a ridiculous 18-2, and people might be questioning whether they should really be this good, but their point differential (league-high plus-223) suggests that their record is right on track with how good they are. They’ve had the league’s easiest strength of schedule so far, but their play suggests that it doesn’t really matter.

On the other side of things, the Rockets rank fourth in the league in winning percentage at 16-4, but only ninth in point differential. In fact, their Pythagorean wins suggest that they should in fact be a 13-7 team at the moment, which would put them at the eighth seed. However, we’ll again withhold judgment since this team has only played four total games with their preseason starting five. When Dwight Howard and Terrence Jones return, we’ll see just how good this Rockets team will be this year.

The Memphis Grizzlies are another fast-start Western Conference team at the bottom of this list. They’re Pythagorean wins suggest that they should be more like 15-6 instead of 17-4, which would put them seventh in the West standings. They’ve had an average schedule so far, but it’s probably been a bit easier than the numbers indicate –- a couple of their games rated difficult, but those teams were missing a good player for the night (they’ve already caught the Rockets twice without Howard and Jones, for example).

The Phoenix Suns’ record is right where it should be according to their point differential so far. However, with the return of Durant and Westbrook, they’ll have to step up their play if they want to hold onto their current eighth seed. Not to mention that the Kings, Pelicans, and Nuggets aren’t too far behind as well. A plus-38 differential is probably not going to be good enough to make the playoffs in the West this year. However, they’re getting back Isaiah Thomas this weekend from injury and are always involved in trade rumors. It will certainly be interesting to see how teams regress to where they should be as the season goes on – what teams are “real” or “fake” to you?