The National Security Agency's collection of phone data doesn't really help in preventing terrorist attacks, according to a recent study by the New America Foundation.
Since 9-11, the group has analyzed 225 terrorism cases. They've found the majority of the time traditional law enforcement provides the tip or evidence to initiate a case.
Last summer, President Barack Obama defended the surveillance programs, but a White House review released last month says much of the evidence "could have been obtained in a timely manner using conventional court orders."
"However, 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," the study said.
The president will announce possible changes to the NSA surveillance program this Friday.