Psychological tests are used to assess various aspects of human behavior, cognition, and personality. They are developed through standardized procedures to ensure validity and reliability. Tests can be individual or group-based, timed or untimed, and involve paper-and-pencil or performance elements. Tests measure constructs like achievement, aptitude, intelligence, interests, neuropsychological functioning, occupational suitability, and personality. They are useful for clinical diagnosis, assessing treatment effectiveness, and evaluating general characteristics and functioning levels. Nurses play an important role by educating patients about tests, creating rapport, observing behaviors, and using test insights to plan appropriate nursing care.