The Westgate Las Vegas SuperBook released its win totals on Sunday for the 2018-19 NBA season, two days after we published our real plus-minus (RPM) projections. As expected, the two measures are quite similar. More than half of the league's teams have a Vegas total within two games of their expected average-wins total from RPM.
Yet inevitably, there are places where RPM diverges from Westgate's efforts to balance the betting on both sides of the total -- starting with the Los Angeles Lakers, whose win total for 48.5 is more than seven wins better than their 41.3-win RPM projection.
What can we take from the differences between Westgate's lines and RPM, and how does it help us locate the betting value?
How RPM has fared relative to totals
We've been publishing RPM projections for the past three seasons. Over that span, just taking the side of the win total favored by RPM has resulted in wins 58 percent of the time. The results get stronger at the extremes. Here are the 10 cases in which team totals exceeded their RPM projections by at least five wins over that span:
Seven of the 10 teams indeed went under, often dramatically so. On the other side of the ledger, teams with RPM projections topping their totals by at least five wins haven't fared quite as well:
While these teams have tended to go way over when they've hit, winning an average of 5.5 more games than their Vegas totals, just 4 of 7 (57 percent) have indeed gone over, slightly worse than the overall average. The potential for lottery teams to fall short of their RPM projections by focusing on draft positioning down the stretch is a risk.
Having considered the track record, let's look at which teams fall into these categories this season.
