Basic true/​false test; reverse stupidity is not intelligence but rationalists tend to have fewer false beliefs. Taking the test upon entering the school would prevent the school from teaching to the test and the test could be scored on multiple areas of which one is a cunningly disguised synonym for rationality and the others are red herrings so that irrationalists have no incentive to lie on the test.
Basic true/​false test; reverse stupidity is not intelligence but rationalists tend to have fewer false beliefs. Taking the test upon entering the school would prevent the school from teaching to the test and the test could be scored on multiple areas of which one is a cunningly disguised synonym for rationality and the others are red herrings so that irrationalists have no incentive to lie on the test.