[michaeloder]

A 10% false-positive rate is awful. If the actual incidence is 2%, a test with that error rate could overstate the results at about 12%. That combined with the sampling bias could easily result in overstated numbers.

Randomized household sampling would be far preferable. That would obviously take much more time and would expose testers and the household to more risk. But without good methods, research like this and the surveys conducted in Santa Clara and LA counties are potentially worst than useless since they have the potential of misinforming policymakers and the public.