What Changed After Serena vs. the Umpire? Not Much.

A year ago, after a heated dispute between Serena Williams and the umpire who cited her for rules violations before she lost the women’s final at the United States Open, there were rapid-fire calls for change.

The rule at the heart of the disagreement — that Williams was being coached from the stands, a charge that her coach later admitted was accurate — was derided as outdated, inconsistently applied, and puzzling for fans and players. The chair umpire, Carlos Ramos, was called sexist, but also praised for enforcing the rules as they were written.

With another U.S. Open about to begin on Monday, tennis leaders are still divided about the 2018 final and its meaning for gender, race and power. The furor has subsided, and no rule changes have been made.

In a fragmented sport with seven governing bodies, there is no consensus on how, or whether, to tackle in-match coaching, an issue that deeply divides tennis, its players and the leadership of the four Grand Slam events.

Fans watching the U.S. Open will see some differences, designed to shed light on rulings. Players’ code-of-conduct violations will appear on scoreboards, along with other match statistics. The new tournament referee, Sören Friemel, and the chief umpire, Jake Garner, will appear on TV during or after matches to explain any rules in question.

“There haven’t been any specific rule changes on any front, but I do think last year’s final has certainly brought a level of awareness to some of the issues that the sport faces,” Steve Simon, the chief executive of the WTA, said in a recent interview.

While in-match coaching remains prohibited at the Open and the other Grand Slam events, it is still allowed on the women’s tour, but not the men’s. Wimbledon and the French Open are against legalization. The U.S. Open and Australian Open are in favor, and are allowing it on a trial basis during their qualifying events.

The U.S. Open this year is encouraging its umpires to give soft warnings before penalizing players for coaching.

A code violation for illegal coaching in Williams’s 6-2-6-4 loss to Naomi Osaka — Ramos saw Williams’s coach, Patrick Mouratoglou, making a gesture in his seat — set off a debate about tennis officiating that spread far beyond the realm of sports. Williams felt the penalty was akin to calling her a cheater and called Ramos a liar and thief, which led to a verbal-abuse penalty that cost her a game late in the second set.

She is back at the Open, dealing with a back injury but a recent Wimbledon finalist. Osaka, who won the Australian Open in January, is back, struggling with a knee injury after a difficult summer juggling expectations of being No. 1.

Ramos, a stickler for the rules who has made no detailed public comments about last year’s final, is returning too, though tournament officials said that he will not work any match involving Williams or her sister Venus. He has not officiated any Williams match since last year’s final.

Ramos has not been assigned to Grand Slam singles final in 2019. His highest-profile singles assignment this year was an Australian Open women’s semifinal. But I.T.F. officials insisted that he was not being marginalized and explained that it was common for leading chair umpires to have variations in assignments from year to year. Ramos did not work a major singles final in 2017.

“I’m glad he’s back with us for the Open,” said Stacey Allaster, the chief executive for professional tennis at the U.S.T.A., which organizes the Open. “He’s a very, very good official.”

That is a different tone than some tennis officials were taking in the immediate aftermath of the match last September, when Williams complained about Ramos, “He’s never taken a game from a man because they said ‘thief.’” Simon of the WTA and Katrina Adams, the president of the U.S.T.A. last year, also suggested that chair umpires were treating women different from men.

Allaster said that the U.S.T.A. could not find any evidence of gender bias at the event, but that “the data set is very limited.” While Grand Slam tournaments reported that men, who play longer matches, received nearly three times more code-of-conduct violations resulting in fines than women over the past 20 years, those raw figures cannot show if women and men were penalized at the same rate for similar incidents and behavior.

Allaster said the U.S.T.A. was interested in working with researchers at the University of Pennsylvania to examine matches for gender bias, but did not yet have enough information to go forward.

So the U.S.T.A. is trying to get some. It has started a database on the circumstances of code violations, and the tournament will use a new video-assistant review system to track play on all courts in real time with a focus on umpires’ rulings and interactions with players.

And for the first time, the U.S.T.A.’s pretournament orientation programs for line judges and the event’s 40 chair umpires include implicit-bias education.

Simon has not retracted his criticism of how Ramos reacted to Williams’s protests, but acknowledged he had not seen evidence of a broader problem either, calling the Williams-Osaka match a “unique instance.”

“It didn’t go well for anybody that was involved in the situation,” he said.

One set of numbers is clearer: From 1998 to 2018, women were fined for coaching violations at Grand Slam tournaments more than any other infraction and are fined for breaking coaching rules more often than men. Through the first three majors of 2019, that trend has held, with 12 fines for women and six for men.

While the rule against in-match coaching stands, Allaster said the Open would encourage its umpires to give soft warnings “wherever possible” and to reserve penalizing players for coaching for the most overt cases.

“It would need to be very clear-cut and the official has seen it and the communication has been received by the athlete,” she said.

The signal from Williams’s coach was obvious, and he admitted making it, but Williams, who was behind in the match and struggling in the face of Osaka’s poise and controlled power, has denied she saw it. Still, a player does not have to see or hear coaching for it to be a violation; according to Grand Slam rules, it is the coach’s behavior that counts.

Mouratoglou said in the aftermath that he was doing the same thing as “100 percent of the coaches in 100 percent of the matches all year long,” yet he also insisted it was the only in-match signal he has sent Williams during their seven years working together.

The belief that illicit coaching is widespread is at the heart of the argument for legalizing it. So is coaching’s supposed appeal to television. Mouratoglou, for one, says that allowing coaching could be a way to help address one of tennis’s biggest concerns: an aging fan base.

The primary counterargument is that full-blown in-match coaching significantly alters the essence of a game in which champions are required to solve problems on their own under pressure. But unanimity is required to change the coaching rules at Grand Slam events. None of the tennis governing bodies is known to have done any formal research with focus groups or fans about in-match coaching.

“To start having coaching in some Grand Slam events and not others creates, I think, a big difference, and philosophically, I think we have to do it all together or not do it,” said Guy Forget, the French Open tournament director.

Patrick Galbraith, a former doubles star from the United States, became the U.S.T.A.’s president in January after Adams’s second term ended. For now, he has adopted a conciliatory approach with the other Grand Slam tournaments on issues like coaching.

Simon is committed to maintaining in-match coaching on the WTA tour, which allows coaching on court once per set but bans it from the stands.

But he said the WTA would be willing to alter its rule if the rest of the sport could agree on a single solution. Next year, he plans to test other formats, aware that on-court coaching has clearer support in North America than in some other markets.

Agreement among the seven governing bodies looks unlikely, but consensus is urgent.

“It’s tough enough for fans to follow our sport and schedule without having to understand 700 different scoring systems and that in one tournament I can talk to a coach and in another I can’t,” said Bethanie Mattek-Sands, a veteran American player who is a longtime member of the WTA Player Council.