"Intelligence" at best is an assumptive construct — the meaning of the word has never been clear. There is more agreement on the kinds of behavior referred to by the term than there is on how to interpret or classify them. But it is generally agreed that a person of high intelligence is one who can grasp ideas readily, make distinctions, reason logically, and make use of verbal and mathematical symbols in solving problems. An intelligence test is a rough measure of a child’s capacity for learning, particularly for learning the kinds of things required in school. It does not measure character, social adjustment, physical endurance, manual skills, or artistic abilities. To criticize it for such failure is roughly comparable to criticizing a thermometer for not measuring wind velocity. Now since the assessment of intelligence is a comparative matter we must be sure that the scale with which we are comparing our subjects provides a "valid" or "fair" comparison.