I've already got http://rt.live/, which is a lot better because it breaks the stats down by state. Lumping everything together into a single number for the entire US isn't useful at all for reasoning about when things will open, or what measures are working. I'm relying on this information to make investment decisions!
> The most precise way to calculate the Rt is directly from medical records that indicate who infected whom. However, this is not really feasible in the current Covid-19 pandemic, because such data are not available for most countries. In the absence of knowledge about infection transmission chains, advanced statistical methods can help to fill this gap. Previous research during the last 20 years have shown that so-called Bayesian inference can be used to estimate most likely infection transmission pathways, which, in turn, allows calculation of the Rt. Our team has relied on these established algorithms and further improved them to calculate the Rt curves for each country. As an input, we primarily use the new infection incidence data that are reported daily. We update our Rt estimations twice a day..
rt.live and this new site use different underlying models.