I'm not sure if you've heard, but the Mavericks are having trouble against their fellow Western Conference contenders. As almost every major site noted in this week's power rankings, the Mavericks have won just one of their games against the seven other playoff teams out West. We're halfway into the season, so this certainly sounds like an alarming piece of trivia. Dallas may be ranked fifth, but judging from their record so far, there's apparently no one they should feel good about seeing in the playoffs.
So is Dallas destined for another first-round exit or is this all a bit premature? The Mavericks may very well be shown the door after one round again this year, because life is unfair and the West is tough. But although we've raised some red flags about this team on occasion, I think there's a good argument to be made that there's nothing about their record that should lead us to this conclusion.
The regular season is long and teams see their conference opponents at most four (and often only three) times before the playoffs. That's just not very many games! There's a reason we make playoff series longer than this. In fact, it's pretty clear that regular season match-ups are a poor predictor of playoff performance.
But before we actually dive into talking about the playoffs and whether regular season records matter, it's worth pointing out what may be the most salient rebuttal to these match-up concerns: it's only nine games. Nine games! Out of 41! That's just over 10 percent of the games they've played this season, and five of these seven teams Dallas has faced only once (the only teams they've played twice are the Spurs and the Suns). Of course, this means that they'll have to see most of these teams two or three more times in the second half of the season, not a particularly friendly schedule. But it also means that they haven't had much of an opportunity to test themselves against the cream of the crop.
The playoffs can be chaotic, but if you're looking to predict how well a team can expect to do, head to head match-ups aren't usually very helpful. Much better is point differential, a metric on which Dallas is currently ranked fourth in conference. Of course, if you have specific concerns about a specific team, it can be helpful to take a more granular look at things. So what happens when teams have to face playoff opponents they've struggled with during the regular season?
Let's look at the playoff opponents the ten most recent NBA champions have faced alongside their regular season match-up records and their point differentials. If you want to see some of the research behind this, there are several studies linked here, but I think this helps illustrate the point made by the relevant analysis:
Over the last decade, eight of the ten NBA title winners have faced (and beaten) at least one team against whom they did not have a winning record in the regular season. Half of them have had at least two such series on their way to the Finals, and half of them had to face teams against whom they lost most of their games that season.
Again, context is important. In some cases these results are reflective of injury. This past season, San Antonio was missing Kawhi Leonard in some of its regular season games against Portland and Oklahoma City, and OKC was missing Serge Ibaka in two of its playoff games against the Spurs, but that doesn't account for most of these results. The majority of these regular season games were played by the teams' usual lineups and in some cases even won by the team sitting good players for rest or due to injury.
This isn't to say that the results of head to head match-ups are completely random or the regular season doesn't matter. Every game is more likely to be won by the better team, and higher ranked teams are more likely to progress in the playoffs. It just means that over the course of a season, all teams will lose some games to teams they're capable of beating, whether because of injury or because luck just didn't go their way that night.
You can see that in the difference in each round of the playoffs on the chart above. No championship team faced off against a first-round opponent they'd lost to in the regular season because the first round usually represents the most lopsided match-up in talent. As the playoffs progress and teams get better, you're much more likely to see teams defeat opponents against whom they had losing records in the regular season (the darker red parts of the chart) because these teams are more closely matched in talent. You can also see the importance of point differential illustrated. It's much less common to beat a team whose regular season point differential was better.
No one likes to lose games, and racking up losses against good teams is demoralizing. But Dallas still has a strong point differential and has faced most of these teams only once. Nine games against seven teams isn't enough information to be this worried. They'll need to win some tough games over the second half of the season, but there's nothing about the first half that should convince you that can't happen.