The wavelike character of virus transmission makes it seem as if transmission is understood by just three critical parameters. But virus transmission is not a physical wave. Virus transmission is affected by measurement error, that is, what’s counted as a confirmation and what’s not counted, and also when it’s counted are subject to error. The counting depends on testing. The tests have measurement error. But more important is that testing is a nonstationary process. The dependence of reported cases or confirmed cases depends on testing. What may seem to be more virus cases spreading may be more tests spreading. But … Continue reading Second Wave? An Opinion