During Monday’s 117-101 Game 1 win over the Philadelphia 76ers, the Boston Celtics looked nothing like an underdog in the series. Behind a combined 83 points from Al Horford, Terry Rozier and Jayson Tatum, the Celtics handed the Sixers their worst loss in almost two months.
Boston couldn’t miss from beyond the arc — the Celtics went 17-of-35 from 3-point range,official nfl jerseys cheap including seven from Rozier in nine attempts and two from center Aron Baynes, half of his career total during the regular season (four) — and Philadelphia couldn’t hit. The 76ers shot 19.2 percent on 3s, their worst accuracy since January.
Yet Second Spectrum’s advanced measure of shot quality told a wildly different story about Game 1. Despite Boston getting more 3-point attempts, Philadelphia’s shots rated better in terms of expected value. Is that reason to believe the Sixers’ chances of winning the series are better than they currently look?
Two years ago, during the 2016 playoffs, I used Second Spectrum’s shot-quality data to back up the cliché that the NBA is a “make or miss league.” Indeed, a team’s shot quality — as measured here by quantified shot probability (qSP), which estimates the effective field goal percentage (eFG) we’d expect based on where a shot was taken, its type, nearby defenders and the ability of the shooter — proved several times less important in determining who won or lost a game than quantified shot-making (qSM), the difference between a team’s actual effective field goal percentage and its qSP.
I also found at the time that shot quality tends to be more sustainable from game to game than shot-making.nfl authentic jerseys So if you’re looking to predict how well a team will shoot in the following game, as measured by eFG, you’re better off considering its shot quality in the previous game than its shot-making.
It turns out, with four-plus years of tracking data for the playoffs, we can now say the same is true for the remainder of the series. Compare how much stronger graphically the relationship is between a team’s shot quality in Game 1 of a playoff series and its eFG in all the remaining games combined, than the same graph with its actual eFG in Game 1 instead of shot quality.