Can cellphone technologies play a role in controlling the coronavirus pandemic? Knowing how public health policies interact with people’s actual behavior, even at an anonymous population-level view, can help guide the decisions of leaders. Mobile phone location data can reveal large-scale patterns of activity and travel between regions. In this episode, associate professor of epidemiology Caroline Buckee explains how such data—carefully stewarded to ensure individual privacy—can even be used to help predict where outbreaks are likely to flare next.