Intelligence and effort is not something that grades can indicate. The fact that students who try are more likely to get good grades is somewhat of a blurring issue. It leads to the assumption that if all students try then all students will do well, and if all students do not try, then all students will fail. This is obviously untrue, and the matter of intelligence is not clear or easy to understand. There are clearly many ways of testing for intelligence, but relying on grades alone to judge somebody’s intelligence will not work.