You cannot tell anything about a person by giving them a test, other than their test-taking ability (you are what you measure). You have to balance it against c

You cannot tell anything about a person by giving them a test, other than their test-taking ability (you are what you measure). You have to balance it against context and other information. If all you do is look at "the score", you're measuring the wrong thing. If your test leads to questions whose answers display competency and skill, you're measuring the right thing.