A study about COVID testing in schools is criticized for its authors’ conclusions. Researchers at Duke, in collaboration with the North Carolina Department of Health and Human Services, studied the “test-to-stay” approach for schoolchildren. With this approach, if a child tests negative after being exposed to someone who tests positive, that child can go to school. Researchers found this strategy to be effective in getting kids back to school—without increasing COVID transmissions.

The trouble, described in a Wall Street Journal opinion piece, is that authors concluded, “in schools with universal masking, test-to-stay is an effective strategy.” The writers explain their thinking:

“That invites readers to assume that test-to-stay doesn’t work without forced masking. But since they studied no unmasked schools, this conclusion is baseless. An honest report would either have said so or not mentioned masking at all.”

The writers believe that study authors are pushing their own agenda for schools to require masking. This is a good example of a study interpretation that is technically correct but omits important information for a fair comparison. In such cases, researchers might hurt their own credibility. On the other hand, do people assume, as the writers say, that “test to stay” doesn’t work in schools without mask mandates?