The original Minnesota Multiphasic Personality Inventory (MMPI) and its successor have been recognized as the most widely used and researched objective clinical personality inventories. Using 567 true-false items, the MMPI-2 assesses a diverse range of personality characteristics; symptoms of psychopathology; and patterns of behavior, attitudes, and concerns. First published in 1942 and revised in 1989, the instrument yields a wealth of clinical data and is used across multiple clinical and medical settings, for employment screening and selection, and in a variety of forensic situations.
The test includes multiple validity indices, assessing test-taking attitudes and approach; 10 basic, numbered clinical scales (1 = Hypochondriasis, 2 = Depression, 3 = Hysteria, 4 = Psychopathic Deviate, 5 = Masculinity-Femininity, 6 = Paranoia, 7 = Psychasthenia, 8 = Schizophrenia, 9 = Hypomania, 0 = Social Introversion, with all but scales 5 and 0 considered core clinical scales) and their subscales; as well as more than five dozen content scales (e.g., Antisocial Practices, Anxiety), content component scales (e.g., Negative Treatment Indicators: Low Motivation), personality psychopathology trait scales (e.g., Aggressiveness, Negative Emotionality/Neuroticism), and supplementary scales (e.g., Addiction Potential, Overcontrolled-Hostility).
Raw scores on these scales are transformed to norm-based T-scores (mean = 50, standard deviation = 10) to enhance the interpretability of results. Scales with a T-score of 65 or greater are considered clinically significant. In addition to interpretive material linked with individual scale and subscale scores, considerable research has identified and supported descriptions associated with particular patterns of elevations, known as code types, reflecting the 1 to 3 most elevated clinical scales and their combinations. As Roger Greene emphasizes, these descriptions are probabilistic statements based on modal patterns and, as such, do not necessarily describe individuals obtaining a specific code. Nevertheless, they provide potentially useful information about problem areas, personality types and correlates, and treatment implications.
MMPI-2 History and Development
The MMPI is an empirically derived test. Through a multistep process, Starke Hathaway and J. C. McKinley developed the original MMPI by selecting items for inclusion that discriminated a criterion group (i.e., those with a given clinical diagnosis) and comparison groups (i.e., nonpatient normative groups and those with other diagnoses). After decades of use, the need for restandardization became clear. As James Butcher and colleagues, Greene, and others have described, several factors underscored the need to revise the MMPI, including the need for current norms, a larger and more nationally representative normative sample that appropriately included ethnic and racial minorities, and updated item content. Those involved in the restandardization took steps to maintain continuity between the MMPI and its revision so that the extant research would not be made obsolete. As Gary Groth-Marnat notes, although some differences have been detected, research has largely supported comparability in findings for the two versions; the MMPI-2 seems to describe the same types of characteristics and behaviors as the MMPI.
MMPI-2 Psychometric Properties
In light of the complex issues involving the MMPI-2’s reliability (many relating to the initial version’s construction), the reader is referred to the readings below for discussions of the test’s development and psycho-metrics. A substantial body of research has supported the conclusion that, with some exceptions, its scales evidence moderate levels of internal consistency and stability over time. Thousands of studies have attested to the test’s validity and the meanings of scale and code type descriptions, as well as the incremental validity obtained when using the MMPI-2 in an assessment.
Recent Refinements of MMPI-2
In an attempt to address issues related to item overlap across the clinical scales and conceptual heterogeneity (i.e., multidimensionality) within them, Auke Tellegen and colleagues published the Restructured Clinical (RC) Scales in 2003. First, they developed a Demoralization scale, thought to represent much of the common “affective” variance shared across the core clinical scales. Subsequent steps were designed to yield scales assessing distinct constructs and resulted in the following: Somatic Complaints, Low Positive Emotions, Cynicism, Antisocial Behavior, Ideas of Persecution, Dysfunctional Negative Emotions, Aberrant Experiences, and Hypomanic Activation. Tellegen and colleagues reported that the RC scales have comparable or greater internal consistencies than the clinical scales, improved discriminant validity, and equivalent or improved convergent validity. They concluded that the RC scales predicted variables linked conceptually to the scales’ core constructs at least as well as and, in some cases, better than the original clinical scales. Leonard Simms and colleagues further documented the increased measurement efficiency of the RC scales, reporting that they were less intercorrelated, related more clearly to measures of personality and psychopathology, and had greater incremental utility than the clinical scales.
MMPI-2 Assets and Limitations
Groth-Marnat cogently summarizes the MMPI-2’s limitations as well as its assets. As he details, issues related to scale construction (i.e., item overlap; high intercorrelations among scales; clinical scale content reflecting multidimensional variables that, in some cases, lack clear definition) are frequently highlighted shortcomings that impact psychometrics and raise interpretive challenges. Numerous authors have also pointed out that the clinical scale names are misleading or confusing because they reflect traditional diagnostic categories (e.g., Schizophrenia) or outdated terms (e.g., Hysteria), and their content does not translate directly to current disorder classification systems. In that vein, he points out that although the test was initially intended as a means of differential diagnoses, it does not provide diagnoses, and research has not supported its utility as a direct diagnostic tool; rather, it contributes information to assist diagnostic formulations and allows for enhanced understanding of symptoms. Other limitations include the test’s length and the fact that although multiple demographic variables (e.g., age, ethnicity, education) may impact interpretation, the onus is on the test user to take such factors into account. Finally, research suggests that moderate scale elevations must be interpreted with caution.
Despite these limitations, numerous advantages lend credence to the MMPI-2’s wide use. Indeed, Groth-Marnat deems its popularity and familiarity assets. In fact, the test has been translated into more than 50 languages and has multiple studies supporting its use in other cultures. The MMPI-2’s extensive research base, detailing the validity of profile descriptors and scale correlates, contributes to this popularity and has been labeled by Groth-Marnat and others as the test’s strongest asset. Furthermore, the test’s multiple validity indices aid the detection of response sets or attempts to over- or underreport psychological difficulties. Consequently, in addition to its standard clinical use, the MMPI-2 can play a role in “gatekeeping” assessments, such as required psychiatric evaluations, employment screenings, or court proceedings.
The MMPI-2 offers substantive value for professionals. Administration is straightforward and may be done via pencil and paper or computer software, and computer scoring and interpretation options are also available. If stamina or time is a concern, the MMPI-2 offers the option of a shorter version that still allows for interpretation of clinical scales and code types. With its revision and restandardization, the introduction of new scales and indices, and the development of the RC scales, the test also continues to evolve to meet practical needs.
- Butcher, J. N., Graham, J. R., Ben-Porath, Y. S., Tellegen, A., Dahlstrom, W. G., & Kaemmer, B. (2001). MMPI-2 (Minnesota Multiphasic Personality Inventory-2): Manual for administration, scoring, and interpretation (Rev. ed.). Minneapolis: University of Minnesota Press.
- Greene, R. L. (2000). The MMPI-2: An interpretive manual (2nd ed.). Boston: Allyn & Bacon.
- Pope, K. S., Butcher, J. N., & Seelen, J. (2006). The MMPI, MMPI-2 & MMPI-A in court: A practical guide for expert witnesses and attorneys (3rd ed.). Washington, DC: American Psychological Association.
- Tellegen, A., Ben-Porath, Y. S., Mcnulty, J. L., Arbisi, P. A., Graham, J. R., & Kaemmer, B. (2003). The MMPI-2 Restructured Clinical (RC) scales: Development, validation, and interpretation. Minneapolis: University of Minnesota Press.