At the start of the second round of the NBA Playoffs, we warned you that things just got challenging in trying to predict the winners. While regular-season games are generally easier to bet than in many other major sports, and the first round of the postseason is often one-sided, things even up quickly as the playoffs advance.
It only took a couple of games in each Conference Semifinal series to establish that this year is no different. There won’t be any second-round sweeps again this year, and many favored teams already find themselves in dogfights and in real danger of not advancing.
The NBA second round is always much tougher to predict than everything that preceded it, but that doesn’t mean that things are random. There are historical trends that can guide us, and many of them are holding up in the brief glimpse we’ve seen of the conference semis this year.
Root, Root, Root for the Home Team
There’s certainly no bubble in the NBA this year. While the postseason two years ago neutralized home-court advantage, it is back with a vengeance this year. In the four second-round series so far this season, home teams are 12-2, for an eye-popping .857 winning percentage.
While home teams haven’t won at quite that rate over time, over the last four years, picking the home team to win has been the best bet you can make in the NBA second round.
Since 2019, home teams have posted a 43-20 record for a .683 winning percentage (excluding the 2020 bubble games, where the home team was in name and jersey color only). It’s been consistently over .600 each season, including 15-9 last year and 16-9 in 2019. For a quick and easy way to determine who is going to win, no other rule of thumb has been anywhere near as powerful or consistent over recent history.
Don’t Rely on the Favored Team
The home-court advantage is more predictive of who will win a second-round game than the last six-plus months of NBA basketball. While home teams have won more than 68 percent of their games, the team with home-court advantage in the series—in other words, the team that had the better NBA regular-season record—has done just slightly better than .500.
This year, the favored teams actually have a losing record in the Conference Semifinals, going 6-8 through the first few second-round games for a .428 mark. That brings the favored teams down to a 44-43 record and .506 winning percentage, since 2019. The better team went 12-12 last season, making the second round a coin flip.
There won’t be any sweeps this year, and it looks like most second-round series are headed for game six or game seven to decide things. That’s certainly nothing new, and it means that you need to have a short memory when trying to bet the Conference Semifinals.
The NBA Playoffs are about adjustments, and the chess match means that momentum is an endangered species as we head into deep water in the playoffs.
The team who won the most recent game in a series has gone on to win the next game just four times in 10 second-round games this year, for a .400 winning percentage. That’s a little worse than what we’ve seen over the last four postseasons. Since 2019, winners of a given game go just 36-35 the next time out, for a .507 winning percentage. So, essentially, knowing who won the last game gives you just a coin toss chance of picking the next game’s winner.
Last year, the winners went on to lengthen their winning streak 12 times in 20 games, the only time they’ve topped .500 since 2019.
The Anti-Momentum Strategy
In fact, momentum is so scarce in the second round that the second-best way to predict a winner (other than just taking the home team) in this round is to pick the team trailing in the series.
This year, the team that leads a given second-round series has won just two of eight times, for a .250 winning percentage. That’s worse than the recent history, but not by a whole lot.
Since 2019, teams leading a second-round series have posted a 19-31 record in Conference Semifinal games for a .380 percentage. That means taking the team trailing a series has won 62 percent of the time.