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Table 2 Country co-variates data and sources

From: The relative effects of non-pharmaceutical interventions on wave one Covid-19 mortality: natural experiment in 130 countries

Measure Reason for inclusion Source
Population density (people per sq. km) As an infectious disease, higher density of population is likely to aid spread
% Population aged 65+ Older persons more vulnerable to adverse effects of infection
% Population male Adverse effect of infection might vary by sex
Life expectancy at birth (years) To adjust for relative baseline health prior to pandemic
Hospital beds (per 1000 people) To adjust for relative hospital capacity prior to pandemic
Physicians (per 1000 people) To adjust for relative workforce capacity prior to pandemic
GDP PPP (current international $) Gross Domestic Product (at Purchasing Power Parity), comparable measure of country wealth and relative average living standard. To adjust for relative deprivation across countries
Manufacturing, value added (%GDP) Healthcare treatment responses to the pandemic required scale-up of various equipment (e.g. ventilators, testing equipment, and personal protective equipment), globally. Extent of manufacturing base might conceivably have changed how a country was able to respond to changes in demand internally
Health expenditure (%GDP) To adjust for relative importance given to health budgets prior to pandemic
International tourism, number of arrivals The virus originated in Wuhan, China. Infectious disease spread from an external source (for all other countries) will conceivably vary by extent of international movement
Governance (Voice and Accountability) Different governance structures might impact when and how policies were introduced, and how strictly they were adhered to. We use a measure which captures the extent to which a country’s citizens are able to select their government, freedom of expression, association and media, i.e. extent of democracy
Region The virus originated in the East Asia & Pacific region (Wuhan, China), so region might affect relative timing of virus arrival and any associated technological/virus evolution changes over time
Testing policy (h2) With Covid-19 testing policy closely tied to attribution of Covid-19 deaths, testing policies will be inextricably linked to the outcome, i.e. more testing will offer more opportunity to attribute a death to Covid-19. We control for this difference by controlling for the extent of testing policy in a given country at a given time
Coding: 0 - No testing policy; 1 - Only those who both (a) have symptoms AND (b) meet specific criteria (e.g. key workers, admitted to hospital, came into contact with a known case, returned from overseas); 2 - Testing of anyone showing COVID-19 symptoms; 3 - Open public testing (eg “drive through” testing available to asymptomatic people)
Contact tracing (h3) As above, contact tracing is closely linked and reliant on testing policy/capacity. We additionally control for the extent of contact tracing policy in a given country at a given time
Coding: 0 - No contact tracing; 1 - Limited contact tracing - not done for all cases; 2 - Comprehensive contact tracing – done for all cases.