Could be that student health services is doing something like that in lieu of testing everyone at regular intervals, and is publishing the results in order to keep the community informed and also so that administration has up-to-date data to use for their decision making.
But that's just my guess at what could be going on.
Probably both
I meant more like how you are figuring out that so many people have covid. Sorry for not being clear.
You could test a random sample and extrapolate.
Could be that student health services is doing something like that in lieu of testing everyone at regular intervals, and is publishing the results in order to keep the community informed and also so that administration has up-to-date data to use for their decision making.
But that's just my guess at what could be going on.