The proliferation of data has always been part of the impact of information and communications technology. Now, as computers and cell phones continue to pervade our daily activities and as millions of networked sensors are being embedded in these devices (as well as in automobiles, “smart” meters, and other machines), the amount of data available for analysis is exploding. The scale and scope of the changes that such “big data” are bringing about have reached an inflection point. Companies capture trillions of bytes of information about customers, suppliers, and operations. Many citizens look with suspicion at the amount of data collected on every aspect of their lives. Can big data play a useful role?