When Rolling Stone took the unusual step of bringing in Steve Coll, the Pulitzer Prize-winning dean of America’s most prestigious journalism school, to dissect its widely discredited article on campus rape, the magazine was clearly making a statement. It was going to get to the bottom of this mess.

Rolling Stone now has what it asked for: a thorough indictment of its behavior.

The Columbia University Graduate School of Journalism report issued on Sunday makes plain in forensic detail what went wrong, how traditional safeguards broke down at pretty much every level of the editorial process. The tone is more constructive than chiding; it is a case study in the failure to follow best journalistic practices.

Now that the facts have been laid bare, “A Rape on Campus,” published in November, joins America’s rogues’ gallery of journalism scandals. For ease of reference, the scandals can be divided into three general categories (excluding the recent phenomenon of television figures telling tall-tale war stories).

The first two are straightforward. There is pure fabrication, for which high-profile culprits include Jayson Blair (The New York Times), Stephen Glass (The New Republic) and, going back a little further, Janet Cooke (The Washington Post). And there is the act of plagiarism (culprits too numerous to list).

“A Rape on Campus” falls into a third category: lack of skepticism.

It is the most complicated of the three, and in many ways the most insidious. It is a crime no single journalist — reporter or editor — can be completely inoculated against committing.

“As an editor, it’s the one that really leaves you feeling you’ve failed at your job,” said Bill Keller, former executive editor of The Times and now editor in chief of the Marshall Project. “The job of editors is to be the last line of defense against reporters who get carried away by an unreliable source, or stampeded by their zeal to break a big story, or who fall for a pat narrative.”

It is a subject Mr. Keller knows well, having presided over The Times’s internal investigation of the paper’s at-times credulous coverage of Saddam Hussein’s supposed cache of chemical and biological weapons in the run-up to the American invasion of Iraq in 2003. In both that case and “A Rape on Campus,” an institution’s better judgment was overwhelmed by its hunger for scoops.

A closer parallel to the Rolling Stone article may be much of the media’s breathless coverage of members of the Duke University lacrosse team who were accused of gang-raping a stripper in 2006. Like “A Rape on Campus,” it was a story that seemed to conform to a lot of the public’s worst ideas about the behavior of privileged young men at elite colleges.

“It was too good to not be true, and that’s what’s going on in this case as well,” said Daniel Okrent, a former public editor at The Times. “You don’t want women to be gang-raped in a fraternity house, but you want to believe this terrible thing is happening and therefore you can expose it.”

On the most basic level, the writer of the Rolling Stone article, Sabrina Rubin Erdely, was seduced by an untrustworthy source. More specifically, as the report details, she was swept up by the preconceptions that she brought to the article. As much casting director as journalist, she was looking for a single character with an emblematic story that would speak to — in her words — the “pervasive culture of sexual harassment/rape culture” on college campuses.

Journalists are often driven to cover atrocities and personal traumas by the best intentions, chiefly the desire to right wrongs and shed light on injustice — in a word, empathy. It is a noble impulse that animates a lot of important and courageous reporting. But empathy can also be a source of vulnerability for journalists, lowering their defenses against bad information.

In the case of “A Rape on Campus,” the risk of being taken in was compounded by Ms. Erdely’s approach. She was steered to “Jackie,” as she referred to the University of Virginia student in question, by a party with a vested interest: a rape survivor and sexual assault activist on campus.

It is hardly unusual for journalists to rely on members of advocacy groups for help finding characters, but it is a practice that requires extra vigilance. “You’re in a zone there where you have to be careful,” said Nicholas Lemann, a professor at Columbia and the journalism school’s former dean.

Mr. Lemann distributes a document called “The Journalistic Method” in one of his classes. It is a play on the term “the scientific method,” but in some respects, investigating a story is not so different from investigating a scientific phenomenon. “It’s all about very rigorous hypothesis testing: What is my hypothesis and how would I disprove it?” he said. “That’s what the journalist didn’t do in this case.”

Sexual assault stories are inherently tough to report. Not only are you encouraging someone to relive a traumatic experience, but you also have to amass enough corroborating detail to be confident in what is essentially an unverifiable narrative. Several years ago, when Kristen Lombardi and Kristin Jones reported a six-part series on campus rape for the Center for Public Integrity, they insisted on including only stories with a paper trail.

Rolling Stone, by contrast, chose to focus on an unreported rape case. The absence of any sort of written records or documentary evidence made it all the more critical to test the veracity of Jackie’s account in any way possible. Instead, the writer and magazine deferred to Jackie’s insistence that they not speak with people who might have — and would have — challenged her story.

The result was a provocative article on a matter of intense public interest that was effectively based on a single, anonymous source.

For all of the answers in the report, which Mr. Coll wrote with Sheila Coronel, the dean of academic affairs at the journalism school, and Derek Kravitz, a postgraduate research assistant there, existential questions remain. From the moment it sprang to life in a San Francisco loft in 1967, Rolling Stone has been true to its anti-establishment DNA. It has been a champion for the legalization of marijuana. Its 2009 article on the financial crisis memorably described the investment bank Goldman Sachs as a “great vampire squid wrapped around the face of humanity.” This is a magazine that likes to raise its voice in support of its causes.

Even in this agenda-driven context, though, Rolling Stone has historically been rigorous. The magazine’s unflattering profile of Gen. Stanley A. McChrystal in 2010 survived what must have been a difficult fact-checking process. But when it was published, General McChrystal took responsibility for its contents, and resigned.

So what happened with “A Rape on Campus”? It is hard not to wonder if gender was a contributing factor. The magazine’s publisher and managing editor, and the editor of the article, were all men. Did that make them wary, consciously or not, of pushing back against a female writer’s account of a young woman’s rape?

For that matter, what role did larger forces in journalism play? By the time “A Rape on Campus” was published, high-profile rape cases had already been reported at a number of colleges. Sexual assault on campuses was becoming part of the daily news cycle. How was Rolling Stone’s article going to be different?

According to the report, Ms. Erdely discovered some other cases of rape at the University of Virginia that had been adjudicated and so would have included a paper trail. None were as “shocking and dramatic.” The magazine stuck with Jackie.

“The hyperactive news world that we live in cuts a couple of ways,” Mr. Keller said. “You have to scream louder to be heard above the crowd. The idea that you would slow down a story, report against your assumptions, dig a little deeper from that other source who might have a different take on things. That runs against the metabolism of the Internet age.”

“A Rape on Campus” was certainly heard above the crowd. It set a web traffic record for Rolling Stone for a noncelebrity article. Its author was profiled in the Style section of The Washington Post. “She was absolutely bursting to tell this story,” Ms. Erdely said of Jackie. (It should be said that The Post also played a leading role in debunking the piece.)

The article’s impact was equaled only by that of the scandal that followed. Within a matter of days, other reporters starting asking the questions that Rolling Stone had not, and Ms. Erdely’s article started to unravel. Her quest to expose the culture of rape on college campuses has now produced a 25-page report on how not to practice journalism.