Non-verbal tests are paper-and-pencil tests that are designed to measure cognitive processes that do not involve verbal language. Such tests use shapes, patterns, diagrams, and sequences to measure general intellectual skills of a non-verbal nature. The use of such tests in schools is described. Performance tests using concrete apparatus are distinguished from these paper-and-pencil non-verbal tests. Major assumptions underlying the use of these tests include: (1) non-verbal tests tap a set of thinking skills basic to intellectual functioning and measure general intelligence; (2) non-verbal tests are more valid measures of the school potential of the low achiever than are verbal tests; and (3) non-verbal tests are culture free. None of these assumptions can be supported. Non-verbal tests appear to measure in the broad domain of intelligence and cannot be disregarded entirely. They are legitimate aids in determining the range and strength of an individual's cognitive abilities, particularly for career planning. It is important to recognize that non-verbal tests provide information for use in conjunction with a variety of sources. (SLD)