2.2. Oxford COVID-19 Government Response Tracker (OxCGRT) Data

Data on government policies implemented to combat the COVID19 spread was retrieved from Blavatnik School of Government and the University of Oxford, The Oxford COVID-19 Government Response Tracker (OxCGRT) dataset [17]. OxCGRT systematically collects information on several different common policy responses that governments have taken to respond to the pandemic on 17 indicators, from more than 160 countries (Table S1). Eight of the policy indicators (C1-C8) record information on containment and closure policies, such as school closures and restrictions in movement. Four of the indicators (E1–E4) record economic policies, such as income support to citizens or provision of foreign aid. Five of the indicators (H1–H5) record health system policies such as the COVID-19 testing regime or emergency investments into healthcare [19].

Of the 17 government implemented policies (Table S1), 12 are aggregated into a set of four indices (Table 1) determined by hierarchical clustering analysis with 1-Pearson’s correlation distance as shown in Figure 1. The policies with the strongest correlation between them and from the same category (starting with C, H or E) were used to calculate indices as shown in the Supplementary Equations S1 and S2. The indices are calculated by averaging the values of clustered policies. Stringency index is provided by OxCGRT which shows overall measure of strictness of government response while the Korean government index quantified from the Korean government’s social distancing levels implemented during the course of the pandemic by the Korean government up to 17 November 2020, which is different from that of the OxCGRT dataset (Table 2) [20]. The variation of the calculated indices with COVID-19 daily confirmed cases is shown in Figure 2. However, C5 variable was excluded from the research because it was not applied in South Korea.

Heat map of the clustered Policies. The Pearson’s correlation matrix of the clustered polices using the hierarchical clustering with 1-correlation distance. H1, H2, H3 form the Health Index, E1, E2 form the Economic Index, C4, C6 and C7 form the Restriction Index while C1, C8, C2 and C3 form the Closing Index.

Variation of Indices with Daily Confirmed Cases Over Time (days). The blue line indicates the index’s level and orange line indicates the COVID-19 daily confirmed cases of South Korea. Each vertical red line represents 30 days difference at x-axis, approximately a month.

Polices used for the calculation of the Indices. The Korean government index represents the Korean government’s social distancing levels implemented during the course of the pandemic by the Korean government.

Korean government Index. The Korean Government Index is quantified from the Korean government’s social distancing levels issued by the Korean government in response to the COVID-19 situations in the country.