The three-phase White House plan, Opening Up America Again, does not detail a national testing strategy or provide numerical benchmarks for how much testing is necessary. It says states should have a “downward trajectory of positive tests” or a “downward trajectory of documented cases” over two weeks, while conducting robust contact tracing and “sentinel surveillance” testing of asymptomatic people in vulnerable populations, such as nursing homes.

Congress is pushing the administration to give states more guidance. The $484 billion relief package passed last week included $25 billion to expand testing and required the administration to come up with a strategic testing plan to support the states.

In the meantime, a flurry of research groups, professors and other experts have stepped in with proposals. On the low end, the liberal Center for American Progress estimates that eight-tenths of one percent of the national population must be tested each week to contain the virus. On the high end, a group from Harvard has put the figure at as much as 21 percent.

Most states — including Georgia, where nonessential businesses have been allowed to start reopening — fall far short of even the lowest estimates.