Google uses location data from smartphones to help health authorities understand how people's movements have changed in response to the global COVID-19 pandemic. In a blog post early Friday morning, Google announced the release of its COVID-19 Community Mobility Reports.
The reports use data from people who chose to store their location history on Google to demonstrate the extent to which people are following government instructions to seek protection locally and, if possible, work from home.
"As global communities respond to the COVID-19 pandemic, there has been an increasing focus on public health strategies, such as social distancing measures to slow the rate of transmission," the company said in a blog post. “In Google Maps, we use aggregated, anonymized data that shows how busy certain types of places are. This way you can determine when a local company is the busiest. We have heard from public health officials that this type of aggregated, anonymized data could be helpful when making critical decisions to combat COVID-19. "
Anyone can view the reports, which initially cover 131 countries. At many locations, users can search for more regional data and review reports for individual states, provinces, and counties. After the user has selected a geographical region, Google generates a PDF with the collected data. Google said it chose PDFs instead of web pages because they were easier to download and share with local employees.
Each report contains information about movement patterns in six categories:
- Retail and recreation with visits to restaurants, cafes, shopping centers, theme parks, museums, libraries, cinemas and similar places.
- Groceries and pharmacies for supermarkets, grocery stores, farmers markets, grocery stores and drug stores.
- Parks that cover public beaches, marinas, dog parks, squares, and other public areas.
- Transit stations for subway stations as well as bus and train stations.
- Work places for offices.
- Residences that cover people's homes.
A sample report from The Verge for California, which has had shelter in place since March 19, showed a sharp drop in retail and resort locations, and transit stations, with a moderate increase in time spent at home.
The data covers the past 48-72 hours, Google said, and the percentage changes reflect the difference between the move this month and late January.
The move comes as technology companies have been asked by government agencies and health authorities to share more data to help respond to corona viruses. On Saturday, the Wall Street Journal reported that mobile advertising companies similarly shared anonymized, aggregated data with disease control and prevention centers and with state and local authorities to help officials understand the spread of the disease and coordinate their response.
Facebook has provided similar data to academic researchers.
Google executives told me that the program was designed to help public health officials prioritize their response to areas of greater need. The reports can help a district official understand that despite being ordered to provide protection, their parks remain crowded – or that their parks are properly empty, but transit stations are still crowded. This would allow them to consider sending messages to their communities about the need to stay away, change or reinforce.
At the same time, a high-level view of changing mobility patterns is likely to be of limited value in dealing with the response to the pandemic. Countries that have been more successful in fighting COVID-19 have introduced aggressive test and contact tracking schemes and used location data invasively. For example, Taiwan uses location data to create "electronic fences" to quarantine citizens and monitor their movements to ensure they stay at home.
Google data does not contain any personal data and does not show the number of visits in a specific category. And it has limits: for example, it may not be able to consider people who spend time near a location as part of permitted outdoor training routines.
The company examined requests from public health officials to provide more contact tracking data. One person's location was used to identify other people who may have been nearby during their infection period. However, Google’s location data isn’t detailed enough to determine if anyone was within 6 feet of them – the distance that is currently believed to put someone at risk – and include them enough mistakes to make contact tracking impractical.
Google also considered using location data to show how crowded hospitals and other medical facilities had gotten. Location data, however, cannot distinguish between healthcare workers, patients, and visitors, which makes the value of sharing such information questionable.
Google plans to update the data in the reports in the future, but has not yet decided when.
Regardless, Google said it would work with epidemiologists working on COVID-19 to update an existing record of aggregated, anonymized information and predict the pandemic's progress.