Final answer:
The MCMI-III is based on both theory, specifically Dr. Theodore Millon's theories of personality disorders, and psychometrics, utilizing statistical measures for reliability and validity.
Step-by-step explanation:
The MCMI-III, or the Millon Clinical Multiaxial Inventory-III, is a psychological assessment tool that draws from both theory and psychometrics. It is based on Dr. Theodore Millon's personality theories, specifically his theory of personality disorders, which provide the theoretical framework for the test. In addition to its theoretical basis, the MCMI-III is also grounded in psychometrics, as it employs statistical methods to ensure that the measurements it provides are reliable and valid. Tests such as the MCMI-III, and its predecessor the Minnesota Multiphasic Personality Inventory (MMPI), which has evolved through versions like MMPI-2 and MMPI-2-RF, use true/false questions to establish a clinical profile and assess various aspects of personality and psychological functioning.