Dr. Alexey Root tested pairs of students on basic checkmates. Beginners were tested on king and two rooks versus king. Intermediates were tested on king and queen versus queen. There was not time to test some of the intermediate students and all of the advanced students.
Before each test, Dr. Root offered to either show how to do the checkmate or go immediately to the test. More than half picked to go straight to being tested rather than having one-on-one instruction on how to do the checkmate first.