Fig. 7.

Estimated ${\widehat{R}}_t$ values in Lombardia computed with the Model-a (grey dotted curve), Model-b (pink dotted curve) and Model-c (blue curve) compared with the measured values of $R_t$ (colored dots). The colors of the $R_t$ dots correspond to the three NPI levels yellow, orange, red. They are delayed by 8 days as computed in the text. For this reason, the first 8 values of $R_t$ are colored in grey since they don’t correspond to any of the three NPI levels here considered. We remind the fitted value ${\widehat{R}}_t(t)$ is set equal to $R_t$ (t) at any change of NPI level