A new study has concluded that the massive collection of phone data by the clandestine U.S. National Security Agency "has had no discernible impact" on preventing terrorism.

A Washington research group, the New America Foundation, said Monday it studied the investigations of 225 people linked in some way to terrorism in the United States since the deadly September 11th attacks and concluded NSA phone surveillance only played a key role in one instance.

The report said the only piece of NSA phone data that had a clear role in initiating an investigation involved a cab driver in San Diego, California, who was convicted of sending $8,500 to al-Qaida’s Somali affiliate in 2007 and 2008.

The New America Foundation said NSA surveillance may have played a role in other investigations, but about 60 percent of the probes stemmed from traditional investigative methods, such as tips from from a family member or informant, or a report of suspicious activity.

The report’s conclusion mirrors that of a White House-appointed review that concluded in December that the NSA’s collection of millions of records of calls made by Americans “was not essential to preventing attacks.”

SOurce: VOA