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Home Is Where the Wins Are

The Celtics haven’t lost in Boston all postseason. Can they clinch an NBA Finals berth with their second road win? Or, with another home game on deck if they can’t, do they even need it?

Getty Images/Ringer illustration

Consider the rookie. A St. Louis native who spent one season at Duke, Jayson Tatum had probably been to Boston a handful of times in his life before this season. Now it’s home. His mom has an apartment a few floors above his, which means when he’s in town he literally enjoys home cooking.

He knows how to get to the arena. He knows what to expect once he gets there. And he knows that when he lights up the scoreboard, the TD Garden crowd will reward him with vocal-cord-straining screams.

Tatum coaxed the crowd to glass-shattering pitches more than once in Wednesday night’s 96–83 Game 5 win over LeBron James and the Cavs. He did it when he had a drive stopped by George Hill, dribbled behind his back to open up a stepback elbow jumper, and drained it. When he zipped a no-look pass through two defenders to a cutting Aron Baynes for a dunk. And when he jumped into a passing lane, tapped the ball ahead to himself, then outran James to the rim for a layup.

The Celtics have often mirrored their young star during this unlikeliest of playoff runs. When Tatum is strutting, scoring 20-plus points in seven straight games, setting rookie records left and right, throwing up three fingers after a splashed trey, and jumping passing lanes for steals like he did Wednesday, the team has clicked on both ends.

Brad Stevens’s offense thrives on quick passes, and on moving the ball and the defense until a good shot becomes a great one or a clogged lane turns into a freeway for Jaylen Brown or Al Horford to power down to the rim. The defense tries to take away an opponent’s preferred option, pushing the offense to less-desirable outlets. Think J.R. Smith dancing with his dribble like a nervous kid at prom and then launching a long 2 that clangs just as loudly as that kid attempting to land a first kiss on someone who’s out of his league.

But Tatum and Co. struggled mightily in games 3 and 4 in Cleveland, losing both by a combined 39 points. The two defeats evened the series, dropped the Celtics to 1–6 on the road in the postseason, and made Game 5 a practical must-win. The Celtics, a below-average offensive team in the regular season, rank ninth this postseason (and last among teams still playing) in offensive rating, at 105.8 points per 100 possessions. They’ve been even worse in the conference finals (103.3), but that’s only because of their performances on the road. Boston has a 107.7 offensive rating at home in the conference finals, compared with 96.6 on the road. Al Horford alone is averaging six fewer points and two fewer shots on the road. The center’s usage is a key indicator for the Celtics: He took eight shots or fewer in four of their six road losses this postseason, including just four in the Game 3 shellacking in Cleveland.

In the first two games at Quicken Loans Arena, the Celtics missed shots they normally make, including a parade of lipped-out layups and clanged dunks that led directly to Cavs points, and played porous defense against an amped-up Cleveland offense (bolstered by resurgent performances from Kyle Korver, George Hill, and Tristan Thompson). Tatum’s point total didn’t exceed his age once in the first four games, and he attempted only two 3-pointers in the two road matchups combined. The lack of production from their key offensive players, more than any lack of a boost from green-laden supporters, has made the difference on the road.

That is not to say that home-court advantage isn’t real. Studies have shown that in the NBA, in particular, playing in front of a friendly crowd seems to boost home teams’ fortunes.

“I truly believe it’s our fans,” Horford said after Game 5, asked about the difference between Boston’s home and road performance. “I feel like our guys feed off of them and it really just drives us as a group. … You get on the road and you’re just out there against everybody else. Here, I just think that our guys just feel comfortable and good. It’s a credit to the atmosphere that’s here.”

That’s an understandable sentiment, and one that has been repeated ad nauseam in this Boston run. (“It’s fun playing in the TD Gahden,” Baynes said after Game 2 against Cleveland, his Aussie accent mirroring the Boston variety in certain places. “All the fans are so smaht and they get behind you at the right times.”) It’s not only coming from the Celtics, either.

“Well, if you watched the first four games, I think both home teams shoot the ball a lot better,” Cavs coach Tyronn Lue said. “They’re comfortable. Their crowd is great, just like our crowd is great. They did a good job protecting home court in Game 5. Now we’ve got to be ready to go in Game 6.”

The Celtics are 10–0 at TD Garden this postseason, the team’s longest run of home playoff wins since a 14-game streak spanning the 1986 and 1987 playoffs, and the longest in the league since … Golden State won a record 16 straight between 2016–17 and 2017–18. The second-longest active streak of home playoff wins? Seven, by the Cavs.

The real advantage, however, may have less to do with loud (and rude) Bostonians affecting the players than it does with their effect on the other people on the hardwood.

Consider the officials. Oh, the poor, unthanked officials.

Imagine yourself in their sneakers. There’s a turnover, and the action suddenly swings to the other end. You sprint your ass off to try to get an angle on a defender who’s using his inside hand to poke at a small ball that’s almost constantly in motion, your vision screened by several mammoth human beings moving faster than should be possible. You have to make a split-second decision — Was it a foul or not? — and act on it. And if your whistle goes against the guys in the home colors, you’re going to hear about it. Loudly.

In their 2011 book, Scorecasting: The Hidden Influences Behind How Sports Are Played and Games Are Won, Tobias J. Moskowitz and L. Jon Wertheim describe their research into foul calls on loose-ball collisions between star and nonstar players in the NBA:

A nonstar player will be assessed a loose ball foul about 57.4 percent of the time, a star player only 42.6 percent of the time. If the star player is in foul trouble — three or more fouls in the first half, four or more fouls in the second half — the likelihood that he will be assessed a loose ball foul drops further, to 26.9 percent versus 73.1 percent for the nonstar. But what if the nonstar player is in foul trouble but the star isn’t? It evens out, tilting slightly against the star player, who receives a foul 50.5 percent of the time, whereas his foul-ridden counterpart receives a foul 49.5 percent of the time. These results are consistent with the omission bias and the officials’ reluctance to affect the outcome. Fouling out a player has a big impact on the game, and fouling out a star player has an even bigger impact. Much like the called balls and strikes in MLB for star players, it is omission bias, not star favoritism, that drives this trend. Star players aren’t necessarily being given better calls, just calls that keep them in the game longer.

One study, on the influence of crowds on referees in the German Bundesliga, showed that more injury time was awarded to home teams in close matches when the host trailed … and that the crowd had less of an effect when there was more distance between it and the officials on the field.

It’s things like that, unconscious omission bias in referees — affecting the game by trying to not affect the game — that likely makes the difference in home-court advantage, especially in a fast, physical game like basketball, played in large arenas with fans literally sitting courtside (and not always acting as passive observers).

Take, for example, one of noted defensive guru Kyle Korver’s blocks on Jaylen Brown in Game 4 in Cleveland:

Brown gathers his own miss, jumps, and extends the ball in his right hand; from behind, Korver either swats the ball away or whacks Brown’s hand, causing the ball to skitter away from Brown and out of bounds. Can you tell definitively what happened? A foul call there would have given Brown two free throw attempts, potentially pulled the Celtics a little closer to the Cavs, and added a foul to Korver’s ledger, thus affecting the way he’d defend the rest of the game.

Now consider this Baynes block on Jordan Clarkson from Game 5:

Does Baynes get all ball, or does he get a little bit of Clarkson’s hand as well? It’s nearly impossible to tell, even when it’s running on a loop. Now imagine having to decide in the moment, with 18,000 people willing you toward one (non-)call.

This is not to suggest that the referees are the reason for the Celtics’ home run (or the Cavs’ run on their home court); that would be foolish, given the average margin of victory in the series is 18 points. (After Game 4, Stevens said you’ll never catch him criticizing the officials.) But it is among the many factors leading to such a dramatic split. For instance, the Celtics defense comes and goes based on location: At home, they’ve given up 86.7 points per game; on the road, they’ve given up 113.5.

It probably doesn’t hurt that the Celtics have one of the lowest average ages in the NBA, and the Cavaliers have one of the highest. “For us to have a young team, fresh legs, and still be able to play like we’re not young is a great feeling,” Marcus Smart said. Meanwhile, Smith attributed the Cavs’ bounceback performance in Game 3 to a three-day layoff. “’Cause we old,” he explained. LeBron also looked exhausted at times Wednesday night, and is carrying the heaviest minutes load of his 15-year career.

“We played with a lot more poise,” Tatum told ESPN’s Doris Burke on the Garden floor immediately after Game 5. “It’s tough going on the road, playing against somebody else in their house, with their crowd. So we were just comfortable. We came back home and defended home court like we have all playoffs.”

Burke, consummate pro that she is, followed up with the logical question: How do you take that success on the road? And despite the friendly environs, Tatum made one of his only mistakes of the evening in his response.

“We’ve just gotta be focused, compoised” — he said, combining composed and poised, before correcting himself — “composed — and play with a lot of poise, and we’ll be fine.”

So far this postseason, that’s been true … at least when the banners they’re playing beneath are green and white.