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.