National Security Agency (NSA) surveillance has done little to stop terrorism, according to a study released on Monday by New America, a public policy institute.

In the report – aptly titled, “Do NSA's Bulk Surveillance Programs Stop Terrorists?” – researchers studied 225 cases of terrorism post-Sept. 11, 2001 and learned that bulk collection of telephone metadata only played a notable role in 1.8 percent of incidents.

NSA surveillance programs prompted an investigation in 7.5 percent of cases, the researchers wrote, adding traditional investigatory work initiated the majority of cases.

“Surveillance of American phone metadata has had no discernible impact on preventing acts of terrorism and only the most marginal of impacts on preventing terrorist-related activity, such as fundraising for a terrorist group,” according to the study.