The National Security Agency's controversial PRISM and phone metadata programs had a "minimal" contribution in the investigation of 225 terrorism cases, a new study finds.

This directly contradicts claims made by President Barack Obama, NSA Chief Gen. Keith Alexander and countless other U.S. officials who insisted both programs had been crucial in fighting and stopping terrorist attacks on U.S. soil.

"We know of at least 50 threats that have been averted because of this information," Obama said at an event in Germany in June.

Months later, Alexander said the two programs helped foil 54 attacks. The phone metadata program played a role in stopping 12 of those "terrorist activities," and PRISM contributed in stopping 53 of the 54 attacks, the outgoing NSA chief said at the Black Hat security conference in August.

But the study, which the New America Foundation published Monday, reached a completely different conclusion.

"Our review of the government’s claims about the role that NSA 'bulk' surveillance of phone and email communications records has had in keeping the United States safe from terrorism shows that these claims are overblown and even misleading," said the research team, led by Peter Bergen, a reporter specialized in national security who also interviewed Osama Bin Laden in 1997.

"Traditional investigative methods, such as the use of informants, tips from local communities, and targeted intelligence operations, provided the initial impetus for investigations in the majority of cases, while the contribution of NSA’s bulk surveillance programs to these cases was minimal," they added.

Their analysis, also published separately in an interactive page, shows that the NSA's phone metadata program only had an impact on 1.8% of terrorism investigations, while PRISM had an impact on 4.4% cases.

That 1.8% refers to only one case in which four suspects were convicted of sending $8,500 to Somali terrorist group Al Shabaab. No actual terrorist attack was alleged in the case.

In more than half of cases, traditional investigative techniques helped initiate the probes. For that reason, the researchers believe that their findings prove the NSA doesn't desperately need these programs to fight terrorism. It already has the necessary tools, without needing bulk surveillance programs.

"The overall problem for U.S. counterterrorism officials is not that they need vaster amounts of information from the bulk surveillance programs," they wrote, "but that they don’t sufficiently understand or widely share the information they already possess."

The New America Study confirms what many had already suspected.

In October, ProPublica published a report showing the lack of evidence behind the claim that the NSA's programs had thwarted around 50 attacks.

Additionally, Marshall Erwin, a fellow at the Hoover Institution and a former counterterrorism analyst in the U.S. intelligence community, published his own study on the NSA's bulk phone metadata program's usefulness. He focused on the two terrorist cases that are often cited to justify it: Khalid al-Mihdhar, one of the hijackers of American Airlines Flight 77, which crashed onto the Pentagon on 9/11, and the 2009 foiled plot to bomb the New York City subway.

"My conclusion is simple: Neither of these cases demonstrates that bulk phone records collection is effective," he wrote in a post on the blog Just Security.

"If we want to ensure the long-term viability of counterterrorism efforts and our continued success against al-Qaeda, we must increasingly prune away those programs and activities that have not helped keep us safe," he said.

After months of claiming it was a crucial tool, John Inglis, deputy director of the NSA, defined the telephone metadata program simply as an insurance policy.

"I'm not going to give that insurance policy up," he said on Friday in an interview with NPR. "It's a necessary component to cover a seam that I can't otherwise cover."

When we reached out to the NSA for comment, they referred us to the Office of the Director for National Intelligence (ODNI), which oversees all U.S. intelligence agencies.

Michael Birmingham, a spokesman for the ODNI, defended the program, arguing that it's a valuable tool.

"But it’s important to keep the program in perspective. This is one of many programs the Intelligence Community uses to identify, track, and disrupt the activities of our adversaries, including terrorists. Neither this nor any other singular intelligence program can, by itself, ensure our national security," he wrote in a statement emailed to Mashable. "Protecting our national security requires a range of tools that allow us to connect the dots. This program is one of those tools."

This story has been updated with comments from the ODNI.

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