I thought they do not, but I see many here reporting their superscore with their decision.
Here’s what I found on one website: “UIUC will take highest composite and highest subscores from different sittings but does NOT recompute a composite score.”
My DS got high scores in individual sections across 3 ACT tests. Is it worth sending all of them, or just the one with the highest composite?
Send all of them. I believe they don’t super score but take best STEM score among those three tests.
They do not superscore SAT’s or ACT’s per se, and use the one with the highest composite but with a twist, in that the colleges may consider a higher section score from another test. For example, the engineering college will use the test with the highest composite for determining composite and most section scores but it will consider a higher math score from another test. So sending multiple tests may help.