Rt.live

Data cited at: Rt.live-https://rt.live/ These are up-to-date values for Rt, a key measure of how fast the virus is growing. It’s the average number of people who become infected by an infectious person. If Rt is above 1.0, the virus will spread quickly. When Rt is below 1.0, the virus will stop spreading. The reason historical values change is that source is not producing a single point each day, but rather a single curve. One of the constraints of the model is that this curve be connected and smooth. So, if new data suggests that R~t~ should be higher, it will pull up previous values so that the newest point is connected. Imagine a rope lying on the ground. If you pick up the end of that rope, the rope needs to slope up to your hand. The same thing is roughly happening with the model. If all of a sudden a testing center releases far more tests than were expected, the R~t~ curve increases which drags up previous values of R~t~. Since case data is staggered in its arrival, a bunch of new cases will sometimes rewrite its view of history given the new data.