This Harvard School of Public Health (HSPH) project combines cell phone data from 15 million people in Kenya with detailed information on the regional incidence of malaria.
According to Harvard University's press release, between June 2008 and June 2009 researchers mapped every call or text made by each of 14,816,521 Kenyan mobile phone subscribers to one of 11,920 cell towers located in 692 different settlements. Every time an individual left his or her primary settlement, the destination and duration of each journey was calculated. Then, using a 2009 malaria prevalence map provided by co-authors at the Kenya Medical Research Institute (KEMRI) and the Malaria Atlas Project to estimate the disease’s prevalence in each location being studied, they inferred each resident’s probability of being infected and the daily probability that visitors to particular areas would become infected. The phone company, Safaricom, provided de-identified business data to researchers that was then used to model the travel patterns of cell phone users. Neither the names of individuals nor their phone numbers were or are known to the Harvard School of Public Health researchers.
By analyzing the incidence of malaria and the movement of people as revealed by their mobile phones, researchers at HSPH and seven other institutions indicated that malaria, in large part, emanates from Kenya’s Lake Victoria region and spreads east, chiefly toward the capital, Nairobi. Such insights help estimate malaria's potential spread and can be used to build a "map of parasite movements" and help better understand the spread of disease.