(R<sub>t</sub>) represents the effective reproduction rate of the virus calculated for each locale. It lets us estimate how many secondary infections are likely to occur from a single infection in a specific area. Values over 1.0 mean we should expect more cases in that area, values under 1.0 mean we should expect fewer.
R<sub>t</sub> Live is tracking daily transmission rate values across the US States. My home state of Arizona is currently in a downward trend with an R<sub>t</sub> right now of 0.77:
(SORRY, LOST IMAGE)
Looking at the daily case numbers, you can see how small rises in R<sub>t</sub> result in muliplicative rises in case numbers:
(SORRY, LOST IMAGE)
We are noticeably flattening the curve in Arizona since late March, but opening up businesses and social gatherings any time soon will change these trends for the worse.