In recent days, as fallout from the Weinstein sexual abuse allegations spreads beyond Hollywood, a decidedly optimistic narrative has taken hold. This is a watershed moment – a tipping point that will come to mark a dramatic change in society’s treatment of sexual harassment and sexual assault in the movie industry and beyond.

It is understandable that this moment has taken on a collectively self-congratulatory cast. The swift and nearly universal condemnation of Weinstein following revelations in the New York Times and the New Yorker is undoubtedly a sign of progress, mostly because the women who came forward were believed unlike countless others in the past.

I have a forthcoming paper on “credibility discounting” in sexual violence cases, which gives me a special appreciation for the reaction to Weinstein’s accusers. But this appreciation is tempered by the knowledge that credibility discounting – an undue failure to believe an account due to bias – will continue well after the dust settles on this appalling casting couch.

To be sure, allegations against Weinstein are terribly familiar to the many women who have experienced much the same. Even so, the Weinstein case is also unusual, primarily because of the sheer number of accusers. Until we grapple with this reality, the progress we are celebrating will remain incomplete.

As of this week, more than 40 women have alleged that they were sexually harassed or assaulted by the movie mogul. Originally, when the story first broke, fewer accounts had surfaced. Yet the fact that not just one woman, but many women, came forward to describe Weinstein’s abuse is hugely significant.

We might call this credibility in numbers. The accounts of multiple women are needed to corroborate one another – that is, to show that an accusation which, on its own, would likely be discredited, can be believed when considered along with a constellation of similar allegations.

The Weinstein accusers are not alone in facing this particular hurdle. Credibility in numbers means that men like Bill Cosby – whose accuser ranks now stand at 58 – can be vigorously condemned in the court of public opinion.

Likewise, recent high-profile cases involving Roger Ailes, Bill O’Reilly and Donald Trump featured clusters of women coming forward. At least by the measure of public sentiment, enough women were together able to surmount the barrier of skepticism that remains in place when allegations of sexual misconduct arise.

But what happens, as is typically the case, when a lone woman reports sexual harassment to a supervisor, sexual misconduct to a college administrator, or sexual assault to a law enforcement official? Often nothing – which helps to explain why the vast majority of women opt not to divulge their sexual abuse, whether in the workplace, on campus, or through the criminal justice system.

In the Weinstein case, one woman, alone, did come forward soon after she was abused. In 2015, Ambra Battilana, an Italian model, promptly reported to New York police officers that Weinstein had grabbed her breasts after asking if they were “real”; he then put his hand up her skirt.

After investigation, prosecutors determined that a case was not provable and declined to bring charges, notwithstanding a recorded conversation in which Weinstein admitted to touching Battilana’s breasts. (Disclosure: I worked in the New York County district attorney’s office 15 years ago.) According to reports, Battilana’s credibility became an issue after prosecutors learned that she had backed away from a previous sexual assault complaint and was untruthful about a past consensual relationship.

Along with a fear of retaliation, the prospect of just this reaction – disbelief – for years kept the many other women from disclosing Weinstein’s abuse. As one accuser recently explained: “Telling others meant ‘I’ll never work again and no one is going to care or believe me.’”

In the Cosby case, the deadlocked jury suggests a similar distrust of a lone woman’s accusation. Andrea Constand was the only victim whose allegation resulted in a criminal prosecution. (Due to the passage of time, the statutes of limitations on the other dozens of accusations had lapsed.)

Her account, along with the testimony of a “pattern and practice” witness who described also having been drugged and sexually violated by the actor, was not sufficient to persuade jurors of Cosby’s guilt. Despite a good deal of corroboration of Constand’s account – more than can be gathered in the typical case – it was not ultimately credited.

Since most sexual abuse allegations begin as “he said, she said” contests, credibility in numbers is not a solution to the problem of discounting. Every single accuser deserves a fair assessment of the allegation – that is, one not derived from an unwarranted baseline of skepticism. This means that credibility must be judged without regard for race, socioeconomic class, or immigration status, to name just a few of the factors, apart from gender, known to trigger longstanding biases in sexual violence investigations.

Regardless of how the Weinstein scandal ends, scores of famous actresses have now validated an experience that has long been dismissed as false or trivial. This portends a frontal attack on rampant sexual harassment in Hollywood and perhaps other industries. Without minimizing the significance of this development, we should demand even greater change. Credibility by the numbers cannot be the endpoint. A lone allegation of sexual abuse by even the least powerful among us requires fair treatment.