Researchers studying the spread of disease can have a difficult time getting reliable information about how populations of people travel between locations. Thankfully, said populations do tend to wander around with tiny electronic transmitters in their pockets. In other words, by tapping into cell phone records, researchers are at last beginning to explore how to make more accurate epidemic models in anticipation of when the next big disease outbreak hits. Flavio Finger of the École Polytechnique Fédérale Lausanne in Switzerland put the cell phone data to the test in Senegal, Discover reports.