The Minnesota Multiphasic Personality Inventory (MMPI) is one of the most widely used self-report personality tests, featuring a true/false question format. First published in 1943 with 504 questions, it was developed using a limited sample of Minnesota farmers and psychiatric patients. The inventory was updated in 1989 to the MMPI-2, which expanded to 567 questions and was standardized using a more representative national sample. A more recent version, the MMPI-2-RF, was released in 2008 with 338 questions, taking about half the time to complete. Despite the newer version's efficiency, the MMPI-2 remains more established and is more commonly used. The test is typically administered via computer. In addition to its clinical scales, the MMPI also includes validity and reliability scales to assess the truthfulness of responses.