It's not Big Data, but Little Data, that Prevents Terrorist Attacks

Many Americans are worried by what we have been learning about the National Security Agency (NSA) and its extensive surveillance programs. It appears to many of us that the government wants to snoop into every aspect of our lives, including "metadata" about our phone calls, information about our Internet use, and who knows what else. This concern is understandable, because these intelligence collection programs do appear to suck in a tremendous amount of data about ordinary Americans?not to mention about people from other countries. And American history shows that intelligence and law enforcement agencies often start out gathering information for a good purpose, but then mission creep sets in and they collect more, and use it for other purposes, than was originally intended. What should we make of all this? It helps to start by understanding how the data collected by the NSA programs may be useful to the U.S. intelligence community.