Stat Chat: the court’s favor

Stat of the week: 17, the number of years since an American man last won the U.S. Open

Under the bright lights at Yankee Stadium, the home team enjoys raucous applause for every hit and strikeout in their favor. When the players first take the field, spectators in center field chant their names one at a time, with the “bleacher creature” fans only moving on to the next player once they receive a wave of the glove or tip of the cap. The players seem to reluctantly acknowledge these fans, but as they get into position in advance of the next pitch, you can expect to see a wide grin on their faces.

The atmosphere in Madison Square Garden is also electric and empowering for the Knicks. The lighting remains unchanged when their opponents take the court, their names being announced monotonously. But just before the Knicks emerge from the locker room, the lights go dark. A spotlight shines on each player as they make their way through a line of high fives, the crowd screaming as the announcer’s voice booms throughout the arena.

Players revel in the cheers and traditions they experience as the fan favorites when they’re playing at home. But what does it mean to be a fan favorite in the age of COVID-19? 

Without fans in the stands, some question whether home field advantage even matters anymore. But fans aren’t the only factors that make playing at home desirable. Since baseball teams this season and historically have played roughly 50 percent of their games at home, players usually have a semi-permanent residence in their team’s home town. Often, their families reside there as well. It’s much easier to play a game after sleeping in your own bed, as opposed to a lonely hotel room. On the other hand, even though MLB opted to not play all of their games in an enclosed compound, travel is being severely limited. There will be no red-eye, cross-country flights after late night games, where having to stay in a hotel room after landing often hits the hardest.

It’s still hard to say just how important fans are, even as we see games played without them for the first time. The league is still assuming that home field advantage is significant enough to be the main edge held by top seeds in this year’s expanded playoffs. Mike Petriello at MLB.com investigated this when home teams were barely above water; on August 17, their record this year stood at 155-152, good (or bad) for just a 50.5 winning percentage. This would have marked the lowest winning percentage for home teams in the history of MLB. However, as of August 26, home teams had inched back up to 53.3, improving their record to 236-207. This is more in line with the approximately 54 winning percentage of home teams historically. Perhaps teams have become more accustomed to the lack of fans in their home parks, or the fake crowd noise is beginning to get into the heads of opposing teams, even if it doesn’t include booing (luckily for the Astros; their worse than usual record this year must be more a reflection of their newfound inability to cheat). 

22-year-old Taylor Fritz (left) and 35-year-old John Isner (right). This year’s unorthodox U.S. Open presents a similar opportunity for the top two American men, despite them representing different stages of a tennis player’s career.

The NBA represents another interesting case study. Playing in a bubble at the Walt Disney World Resort, with players not allowed off the compound, home court advantage is entirely manufactured. Music, audio and graphics from the “home” team’s actual home arena serve to create this advantage. So far it seems to have worked, as home squads have gone 19-15 in the playoffs as of August 27, good for a 55.9 winning percentage. Although the sample is pretty representative (14 of 16 teams have played two home games, while the other two have played only one more), it is very small, so it’s hard to make any sweeping conclusions. If home teams had lost just two more games, their record at 17-17 would have dropped their winning percentage all the way down to 50.

With the U.S. Open beginning on August 31, I wondered how results might differ in tennis based on the changes in home court advantage (or disadvantage). Specifically, I examined the differences in winning percentages for American men (the data for women are unfortunately not available on the most comprehensive site) who played at least 15 matches in the U.S. Open (sample one) versus those who played at least 50 total Grand Slams matches, including their U.S. Open matches (sample two). I chose the numbers 15 and 50 because they provided similar sample sizes (81 and 64, respectively, with 62 players meeting both criteria). Since the “all Grand Slams” sample included the U.S. Open, I could use a paired-samples t-test, which essentially isolated the effects on winning percentage when adding the other Grand Slams (since adding the other Grand Slams was the only factor that changed between the two samples) by looking at the differences in the means from each sample. The difference between the means was very insignificant (p = .741) at .290 percent, with Americans actually performing slightly better on average in Grand Slams overall as opposed to just the U.S. Open. This left me scratching my head. 

But eventually I put the pieces together. I had initially looked into how Americans performed in the U.S. Open (minimum 15 matches) relative to all big tournaments (finals, masters, olympics, and Grand Slams; minimum 100 matches). 62 players met the minimum match criteria. This yielded a significant result (p < .05), with Americans performing better in the U.S. Open-only sample by 2.10 percent on average. I realized, however, that some of these other big tournaments, besides the U.S. Open, also took place within the U.S. So, I hypothesized that what really makes Americans play better is playing in a Grand Slam. Sure enough, when comparing Grand Slams to other big tournaments (63 players met both minimum matches criteria), Americans performed better in the Grand Slams only sample by 2.53 percent (p < 1^-7) on average.

While it may not necessarily be home fans that energize Americans, they definitely seem to do best at the most crowded events—fans in general energize them. But this was not unique to Americans; in fact, the results were more robust when comparing the performance of non-Americans in Grand Slams to their performance in all big tournaments. 232 non-Americans met the minimum match criteria. They performed significantly (p < 1^-15) better in Grand Slams than in all big tournaments, outpacing themselves by 3.12 percent on average. Tennis is unique in that to meet these minimum match criteria, you really need to win (winning means playing another match). So maybe this conclusion only holds true for those who play well enough under pressure to advance; of course players who thrive in a high-stakes environment will prefer playing in front of more fans.

Regardless, since the effect of fans (for or against) is more positive for non-Americans, perhaps Americans will actually benefit from the emptiness of the stands at this year’s U.S. Open. It has been 17 years since the last time an American man won the biggest prize on his home turf. With no fans and a limited draw without the likes of Roger Federer and Rafael Nadal but with the top two Americans, this year may represent the best shot in recent memory that the United States has at recapturing the Open’s men’s title.

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