| Ex. ECO-B-099 | WMATA, 'COVID-19 Information: Service Changes due to the public health emergency' (page as of May 13, 2020)WMATA COVID-19 service changes: reduced Metrorail and Metrobus service, station closures and rear-door boarding during the public health… | Washington Metropolitan Area Transit Authority | District of Columbia, Maryland, Virginia (Washington Metropolitan Area Transit Authority)State | Mar. 16, 2020 | 2020 Q2 | Travel and quarantineOther | Primary source read | |
| Ex. ECO-B-105 | Ballotpedia, 'School responses to the coronavirus (COVID-19) pandemic during the 2019-2020 academic year'State-by-State chronology of spring 2020 school closure orders and announcements, with total students affected per State (NCES) | Ballotpedia (secondary source; student counts from NCES) | United States (50 States and D.C.)Other | June 30, 2020 | 2020 Q2 | Schools and child care | Confirmed from a secondary source | |
| Ex. ECO-B-106 | Ballotpedia, 'School responses to the coronavirus (COVID-19) pandemic during the 2020-2021 academic year'State-by-State chronology of 2020-21 reopening orders, statewide closures (Kentucky Nov. 23, 2020; Michigan Nov. 18, 2020), in-person… | Ballotpedia (secondary source; Burbio data) | United States (50 States and D.C.)Other | July 8, 2021 | 2020 Q32020 Q42021 Q12021 Q2 | Schools and child care | Confirmed from a secondary source | |
| Ex. ECO-B-155 | Mayor's Order 2021-097 (July 29, 2021), indoor mask requirement effective July 31, 2021, applied to schools and child care for 2021-22District of Columbia indoor and school mask requirement, 2021-22 (schools to Mar. 8, 2022) | Mayor Muriel Bowser | District of ColumbiaState | July 29, 2021 | 2021 Q3 | Face-covering requirementSchools and child care | Primary source read | |
| Ex. ECO-B-107 | Ballotpedia, 'School responses to the coronavirus (COVID-19) pandemic during the 2021-2022 academic year'State-by-State table of 2021-22 school mask requirements and bans (instrument type and end date) and teacher/staff vaccination requirements… | Ballotpedia (secondary source) | United States (50 States and D.C.)Other | Aug. 1, 2022 | 2021 Q3 | Face-covering requirementSchools and child careVaccination or testing | Confirmed from a secondary source | |