Google will publish from Friday statistics from the location data of its users around the world, to help public authorities assess the effectiveness of social distancing measures against the Covid-19. Downloadable on a dedicated site for more than 131 countries including France, these reports must reveal the ” general trends of the movements of people over time and by geographical area, in different categories of places such as places of leisure, shops grocery stores, pharmacies, parks, public transit stations, workplaces and homes, “ according to an article on a blog by the American giant.
“We will display trends over several weeks” in the form of ” an increase or decrease in the percentage of visits” , and not an absolute number, specifies the article signed by the director of geographic products of Google (including Maps) Jen Fitzpatrick and Google’s chief doctorHealth Karen DeSalvo. The most recent information will date from “48 to 72 hours”. We thus learn that in France, the frequentation of leisure places (restaurants, cafes, shopping centers, theme parks or museums) decreased by 88% compared to normal, that of local shops fell by 72% after a peak at + 40% when the confinement was announced, and there was half the traffic (-56%) in the office areas. These proportions vary according to the severity of the containment measures taken in the different countries, but they do not allow the displacement of populations between regions to be studied.
” We hope these reports will help (public health officials) make decisions about how to manage the Covid-19 pandemic.” For example, this information could help managers understand changing trends in essential travel, which could lead them to make new recommendations regarding opening hours or delivery service offerings , “said Google.
“Differential confidentiality”
Like traffic jam detection or the measurement of traffic on Google Maps, these reports use “aggregated and anonymized” data from Google users who have activated “location history” , which can be deleted or interrupted in the settings Account. ” To protect people’s privacy, no personally identifiable information, such as a person’s location, contacts or movements, is made available,” Google writes. To prevent any attempt to identify a person in the data set, the company has implemented a statistical technique called ” differential confidentiality” which adds “noise” to the raw data while keeping statistics close to reality.
Various technological projects have been launched around the world to fight the epidemic, in particular the use of location data from telecom operators to predict the spread of the virus and trace the course of sick people, or to mobile applications to alert users to ‘they crossed paths with infected people.
