Study population and setting
The authors compared daily mobility before and after state-level emergency declarations were in place at the county and census tract level in the US. Mobility data were collected between January and April 2020. Four different mobility measures were used: being completely at home (SafeGraph); median distance traveled (SafeGraph); device exposure (the number of unique devices visiting a particular venue, Place IQ); and visitors to retail and recreation places (Google Mobility). Census tracts and counties were classified based on median income quintile to see if county or census tract mobility varied by average income levels. Additionally, the authors controlled for the cumulative number of COVID-19 infected cases in each county at each time point.
Summary of Main Findings
Wealthier census tracts and counties had markedly reduced mobility following statewide declarations. This suggests that wealthier areas are more likely to respond or have the ability to respond to social distancing measures. These results were broadly consistent across the four mobility measures (completely at home, median distance traveled, device exposure, and retail and recreation).
The study uses multiple measures and databases to compare mobility at the county or census tract level before and after state-wide declarations are in place across measures of county or census tract level income levels, providing a more comprehensive view of changes in mobility.
Several other factors beyond income may influence the tendency or ability to socially distance once mandates are in place. For example, one’s occupation will influence the ability to telework, with higher incomes associated with jobs more likely to be able to be done from home. Individual willingness to socially distance may depend on political views, culture, and beliefs and these may cluster at the county or census tract level. Housing also varies by county and census tract, and may influence the ability to distance. As the authors acknowledge, even though we observe differences in social distancing by income level, it is unclear what drives this difference. A second key limitation is that analyses were conducted at the aggregate level, and cannot directly examine whether individual’s income levels relate to mobility.
Using multiple mobility datasets, the authors show that wealthier areas had markedly greater reductions in mobility compared to poorer areas.
This review was posted on: 3 September 2020