Tests are used in guidance to measure various traits of individuals. There are several types of tests used including achievement tests to measure educational progress, aptitude tests to assess learning potential, interest tests to discover preferences, diagnostic tests to identify weaknesses, and intelligence tests to determine cognitive ability. Personality tests, which can be projective like the Rorschach test or non-projective through questionnaires, aim to understand the whole personality. Test results provide data to benefit students through improved instruction, career guidance, and identification of support needed.