Students and staff in a high school had 762,868 encounters in a single day.
Scientists tracked the movements of everyone in a high school for a day.
The research helps explain how diseases like the flu can move through a population.
Using such models, scientist hope to better predict, and then limit, the spread of infectious diseases.
Last January several hundred bleary eyed students filed into an unnamed American high school to accept an unusual assignment: wear a matchbox-sized device around their neck for the day.
As the students passed each other in the halls, lined up for lunch, and listened to their teachers and administrators (who also sported the boxy jewelry), the devices recorded every encounter, or occasion when the devices came within 10 feet of each other. Ten feet is considered the maximum distance that spit, phlegm, or snot infected with influenza can travel.
By the end of the school day the devices had recorded an astonishing 762,868 encounters among the students, staff, teachers and administrators of the high school, far more than the scientists from Stanford University were expecting or had been reported before.