Policy and Law Assessment of COVID-19 Based on Smooth Transition Autoregressive Model

Figure 1

The fitting result of Guangdong Province, China. The left axis shows the daily confirmed cases for the real data after smoothness (blue solid line) and its fitted values by the STAR model (blue dashed line). The right axis shows the value of nonlinear functions changing with time (orange solid line) and the reference line with threshold 0.5 (orange dashed line). The vertical dotted line indicates the sequential released policies: ① close entertainment and gatherings, ② close other places, ③ isolate confirmed cases, and ④ suspend urban traffic.