J Med Internet Res. 2020 Oct 11. doi: 10.2196/21499. Online ahead of print.
BACKGROUND: Social distancing is an important component of the response to the novel Coronavirus (COVID-19) pandemic. Minimizing social interactions and travel reduces the rate at which the infection spreads, and “flattens the curve” such that the medical system can better treat infected individuals. However, it remains unclear how the public will respond to these policies as the pandemic continues.
OBJECTIVE: We present the Twitter Social Mobility Index, a measure of social distancing and travel derived from Twitter data. We use public geolocated Twitter data to measure how much a user travels in a given week.
METHODS: We collected 469,669,925 geotagged tweets from January 1, 2019 to April 27, 2020 in the United States. We analyzed the aggregated mobility variance of a total of 3,768,959 Twitter users at the city and state level since the start of the COVID-19 pandemic.
RESULTS: We found a large reduction (61.83%) in travel in the United States after the implementation of social distancing policies. However, the variance by state was high, ranging from 38.54% to 76.80%. The eight states that did not have statewide orders as of the start of April ranked poorly: Arkansas (45), Iowa (37), Nebraska (35), North Dakota (22), South Carolina (38), South Dakota (46), Oklahoma (50), Utah (14), Wyoming (53). We present our findings online and will continue to update our analysis during the pandemic.
CONCLUSIONS: We observed larger reductions in states that were early adopters and smaller changes in states without policies. The results are also consistent with the ones based on other mobility data to certain extent. Therefore, geolocated tweets are an effective way to track social distancing practices from a public resource, suggesting that it can be used as part of ongoing pandemic response planning.