So the CDS unfortunately does not contain good data on test submission for applicants as opposed to enrolled students.
But I think it is a good bet that at least, say, 60% of the applicants to a college like Yale submitted tests (with enrolled students ending up higher).
So for the Class of 2028, Yale had 57517 applications, which implies to me something like at least 34000 applicants submitted a test. Possibly more.
OK, so back in the 2019-20 CDS, Yale was still test required, and it got . . . 36,844 applicants. Given how rough all this is, I would agree those are more or less the same number within the margin of error. Meaning it does indeed look like at Yale at least, going test optional did not in fact significantly cut the number of applicants who submitted test scores.
And I think there are obviously going to be cases of people who would have applied to Yale either way, and so some of the recent test optional applicants very likely would have applied to Yale with test scores if they had to.
So yes, all this helps explain why MIT saw only mildly fewer applications when it went back to test required, and it didnât go all the way back down to the levels of the earlier test required period. Lots of applicants were submitting tests to MIT anyway, others were not deterred when they had to submit, and so it was only a modest minority fraction that actually did not apply due to the change back in policies.