Fig. 4.
Comparison of the predicted and observed acceleration of COVID-19 cases over 5,642 wk for 211 territories in leave-one-out cross-validation. (A–D) Weekly acceleration of daily COVID-19 cases (A) is predicted using (A) the OxCGRT NPIs, (B) PHSM NPIs, (C) human mobility, or (D) alternatively NO2 change (ΔNO2) as predictors, while other predictors including 10 socioeconomic and environmental indicators are identical. To evaluate the skill in predicting the deceleration of COVID-19 cases, the MSE is weighted by a function of (0.99)h, where h is the rank of the observed A. For example, the weighting factor decreases from 0.99 for the lowest A to 0.0000436 for h = 1,000. The coefficient of determination (R2) is defined as 1 minus the ratio of MSE to variance in the observation. Moving averages of A at an interval of 50 are shown by thick lines in different colors. (E) As in D, except for using the data filtered by precipitable water content in the air above the median and NO2 concentration below the median.