[mike_hearn]

Other types of test are calibrated against PCR tests. That's why the article says:

"[...] finds the largest study to compare home rapid tests with gold-standard PCR tests"

PCR is assumed to be the truth to which rapid tests should aspire.

> False positives with rapid tests are known to be far less prevalent.

That's probably true if you use a normal definition of false positive, but under the intellectual framework public health uses you can't say this because you can't have less prevalent than zero.