2.1. Data sources
Individual-level COVID-19 case and mortality data from March 2020–February 2021, including residential address and date of diagnosis or death, were provided by MDPH. Residential addresses were geocoded using a cascade matching geocoding method developed by combining MassGIS Address Points for Geocoding and ArcGIS Business Analyst geocoding locators (© Esri, Redlands, CA), and assigned to the census tract associated with home locations (1462 tracts within MA after dropping five tracts with zero cases or zero population). Cases and deaths were aggregated into two time periods for analysis: “Phase 1” (March–June 2020) and “Phase 2” (September 2020–February 2021). The 2020 summer months were a period of reduced COVID-19 burden of cases/deaths in MA; the exclusion of those months in our modeling allowed comparison of periods of time with similar levels of disease burden.