“Big data” in government are the topic of the moment across the world. Public sector datasets have evolved to include large volumes of very diverse sources of information. They raise issues of privacy, security or information sharing, but also of design and training. To make good use of big data, public managers have to ask the right questions. Not only on the data but also to a new generation of “data scientists” on whom they depend. The post discusses five key points about how public managers need to prepare for working with big data.