The evaluation is based on the idea that the turning point of the pandemic is at the plateau, which the gradient is zero. This vitalization is to show the relation between the confirmed case with its growth, and the active cases (patients) with its growth.
Country which has been passing the plateau will start having negative growth for active cases. In this case the chart will cross the horizontal axis (e.g. China, Korea, Malaysia and Italy). On the other hand, there are countries that are still fighting with the transmission growth
How to read the chart