Sure, that may be true of ELO-based games. In the realm of the standardized tests used for school admission, we also have a lot of data about performance so we

Sure, that may be true of ELO-based games. In the realm of the standardized tests used for school admission, we also have a lot of data about performance so we can use that data instead of looking for analogues in other fields. And my experience with the SAT & ACT leads me to believe that on these tests, the difference between 1% and 7% could be something as simple as how well the student slept the night before the test.