It was one of the most famous apologies in modern American history: On a Monday night in August 1998, after seven months of denials, then-President Bill Clinton delivered a speech admitting to a sexual affair with Monica Lewinsky. Sounding stony—and, at some points,  defiant— Clinton called his behavior  “wrong,” and said it constituted a “personal failure,” for which he was “solely” responsible. “I misled people, including even my wife,” he said. “I deeply regret that.”

On paper, Clinton’s words appear contrite and confessional. Yet nearly two decades later, many who study the psychology of apologies view the address as a four-minute primer on how not to apologize for something. Of course, few individuals will ever have to give a televised mea culpa, but public apologies still hold lessons for the best way to deliver more private ones.

Last fall, for example, the Chipotle founder Steve Ells issued several apologies—including a full-page newspaper ad containing a seven-paragraph letter—for the food-borne outbreaks linked to his restaurant chain. There is evidence that customers feel a sense of restored fairness when companies apologize, provided CEOs show sufficient empathy— a key factor for successful personal apologies, too.

Aaron Lazare, the former dean chancellor and dean of the University of Massachusetts Medical School, wrote a book about the apology, which he called one of the most profound interactions two human beings can have with one another. Research by Lazare and others suggests that effective apologies—meaning those that are accepted by an offended party—all tend to share a set of underlying features. For close relationships in particular, studies have shown that one of the most important elements is timing: When people make the common mistake of saying they’re sorry too quickly, they can miss a crucial step towards reconciliation.

The impulse to apologize instantly may stem from a cultural credo that action is always better than indecision—and that waiting implies apathy. “We are primed to react immediately to everything,” said Frank Partnoy, the author of Wait: The Art and Science of Delay. Like the skilled tennis player who waits as long as possible before returning a serve, Partnoy argued, strategic stalling in apologizing often yields the best results: “We feel we need to apologize right away, in the same way we feel we need to respond right away to texts, emails, and 24-hour news.” But if someone commits a serious transgression—say, cheats on a spouse—it’s best to apologize only after the victim has had a chance to “yell and vent” and fully process the betrayal, he said.

Past research has shown that a key part of a successful apology is assuring the victim that the bad behavior won’t happen again. “When we’ve done something wrong, we tend to be self-focused,” explained Cynthia Frantz of Oberlin College, who authored a landmark study on apology timing titled “Better Late Than Early.” “You actually should be more focused on the other person, making sure they really believe that you get what you did wrong.” Without that emphasis on the other person’s emotional state—and the promise of change—an apology sounds insincere.

In 2004, Frantz asked 83 college students to respond to an ordinary social conflict—forgetting to meet a friend for a party, but going on their own—and then to imagine that the friend had apologized at the very beginning of a conversation, after the participants had a chance to voice their feelings, or not at all. Respondents had the most positive reactions to an apology delivered after they’d had the opportunity to express themselves and feel heard by the other party. But Frantz cautioned that the apology curve is most likely U-shaped: Apologies that come too late, like those that come too early, are likely to fail; the sweet spot is somewhere between the two. “[This] could be an hour, a day, a week,” Frantz said. “It depends entirely on the circumstances and the nature of the relationship.”

It may be that later apologies work best for more discrete conflicts, while earlier ones prevail for deeper, open-ended ones. For a 2013 study published in the Western Journal of Communication, researchers videotaped 60 heterosexual couples discussing preexisting relationship issues, like annoying habits or disagreements over how they should spend their time together. For conversations shorter than 10 minutes, the study found, people tended to be more satisfied with a later apology from their partner. But if the conversation lasted longer than 10 minutes, the couples tended to judge their disputes as more damaging— more likely to touch on questions of trust and jealousy, for example—and preferred an apology earlier in the discussion.

Amy Ebesu Hubbard, the study’s lead author and the communicology department chair at the University of Hawaii, Manoa, said the findings suggest that apologies function in several ways. “Showing remorse and seeking forgiveness are only part of the story,” she said. In some cases, an earlier apology served as “a launching pad” for more elaborate conversation, easing tensions between the couple and making it “safe to continue.”

But apologies also have a law of diminishing returns, she cautioned, and overdoing it can make each individual apology feel less sincere. “If you apologize too frequently to someone, it becomes background noise,” she said. “We notice things that stand out of a normative pattern. “

As the linguist Edwin Battistella wrote in his book Sorry About That: The Language of Public Apology, apologizing too easily can also come with social consequences—for example, many people argue that women are disadvantaged in the workplace by a tendency to apologize more frequently than men. (The comedian Amy Schumer’s “I’m sorry” skit captures the phenomenon well, depicting successful women over-apologizing at an “innovator’s conference” to the point of absurdity.)

A 2010 study added greater nuance to the gender stereotype, finding that while men apologized less than women, they also reported committing fewer offenses. “There was no gender difference in the proportion of offenses that prompted apologies,” the authors wrote, suggesting that “men apologize less frequently than women because they have a higher threshold for what constitutes offensive behavior.” A separate study also found that men apologized more frequently to women than they did to other men.

Editors at Oxford Dictionaries recently added an entry for “non-apology,” defining it as a statement that takes the form of an apology but doesn’t sufficiently acknowledge responsibility or regret. Last month, Oxford also added an entry for “apology tour,” a series of public appearances by a well-known figure to express regret over a wrongdoing. Neither term had yet entered the cultural lexicon in August 1998, but both aptly describe Clinton’s trajectory, from the non-apology of that first televised address to the apology tour that followed.

On September 11, 1998, after several smaller-scale re-apologies, Clinton delivered what is considered his successful mea culpa for the Lewinsky affair before more than 100 religious leaders and his wife at the White House’s annual prayer breakfast. “I agree with those who have said that in my first statement after I testified that I was not contrite enough,” he told the audience. This time, his tone was somber and reflective, a far cry from the attitude he’d shown in his initial speech.

“Clinton’s legal training had a lot do with the first bad apology,” said Battistella, who describes apologies as a way of leveling power dynamics between two parties. “Conditional apologies do not work well,” Battistella said. “They are the Jiu-Jitsu of apologies: ‘I’m sorry if you were offended, what’s wrong with you?’”  

And so like anyone else attempting to repair a relationship, the former president had to try again, with greater empathy and specificity. As Lazare often noted, while good apologies have the power to heal, bad ones only make things worse.