Evaluating the Similarity of MMPI-2 and MMPI Profiles: Reply to Dahlstrom and Humphrey

We review issues that have arisen in exchanges with Dahlstrom and Humphrey (Dahlstrom & Humphrey, 1996; Humphrey & Dahlstrom, 1995) about assessing the comparability of the Minnesota Multiphasic Personality Inventory-2 (MMPI-2) and the MMPI. We point out the limitations of Q correlations (without contending that D² is "the only legitimate function of profile comparability," as Dahlstrom and Humphrey, 1996, p. 350, claim we do), and explain why Dahlstrom and Humphrey's (1996) new Q-correlational results, correctly interpreted, are consistent with our own previous observations and conclusions. We stress again the importance of both overall profile elevation and profile "definition" in making code-type assignments. Nonrestrictive code types ignore these profile characteristics, and their use needlessly lowers MMPI-2/MMPI code-type congruences and raises the incidence of profile misinterpretations. Our recommendation of well-defined MMPI-2 code types stands.     

Code-Type Comparability of the MMPI and MMPI-2: Analysis of Recent Findings and Criticisms

The introduction of the MMPI-2 has stimulated studies of its comparability with the MMPI. Graham, Timbrook, Ben-Porath, and Butcher (1991) consider the congruence between MMPI-2 and MMPI code types substantial, but Dahlstrom (1992) has questioned their appraisal, criticizing their use of "well-defined" code types. Our own analysis supports Graham and colleagues' (1991) conclusions and provides reasons for favoring narrow code types (such as well- defined code types) over nonrestrictive ones. We also offer a brief historical review of MMPI code typology as background for our recommendation that future MMPI-2 research not be limited to studies of code-type correlates.     

Code-type comparability of the MMPI and MMPI-2: analysis of recent findings and criticisms

The introduction of the MMPI-2 has stimulated studies of its comparability with the MMPI. Graham, Timbrook, Ben-Porath, and Butcher (1991) consider the congruence between MMPI-2 and MMPI code types substantial, but Dahlstrom (1992) has questioned their appraisal, criticizing their use of "well-defined" code types. Our own analysis supports Graham and colleagues' (1991) conclusions and provides reasons for favoring narrow code types (such as well- defined code types) over nonrestrictive ones. We also offer a brief historical review of MMPI code typology as background for our recommendation that future MMPI-2 research not be limited to studies of code-type correlates.     

How (not) to evaluate the comparability of MMPI and MMPI-2 profile configurations: a reply to Humphrey and Dahlstrom

Humphrey and Dahlstrom (1995) presented a study on the comparability of MMPI/MMPI-2 (Butcher, Dahlstrom, Graham, Tellegen, & Kaemmer, 1989) profiles in which they concluded that "the bases for clinical interpretation derived from the MMPI and MMPI-2 profiles were sufficiently at variance to require different conclusions" [sic] (p. 2). In this brief critique, we identify procedural and data-analytical deficiencies that invalidate Humphrey and Dahlstrom's argument. Their blanket recommendation based on this argument, namely, that clinicians routinely plot both MMPI and MMPI-2 profiles, is unwarranted.     

Comparability of MMPI and MMPI-2 profile patterns: Ben-Porath and Tellegen's inappropriate invocation of Mahalanobis's D2 function

Ben-Porath and Tellegen (1995) claimed that the data in the article by Humphrey and Dahlstrom (1995) were improperly analyzed by means of Q correlations between raw scores earned by the individuals in the forensic sample to establish pattern comparability between the original Minnesota Multiphasic Personality Inventory (MMPI; Hathaway & McKinley, 1943) and the Minnesota Multiphasic Personality Inventory-2 (MMPI-2; Butcher, Dahlstrom, Graham, Tellegen, & Kaemmer, 1989), which were then contrasted with Q correlations between the corresponding T-score patterns. Ben-Porath and Tellegen (1995) contended that the Q correlation is affected by random factors and that a generalized distance function, D2, is the only legitimate index of profile comparability. Data are presented here to show that the Q correlation serves as a reliable index of pattern comparability, relatively unaffected by differences in profile elevation. The Mahalanobis (1936) D2 index is too heavily weighted with differences in profile elevation serve as the proper index of equivalence in profile patterning. The findings in the Humphrey and Dahlstrom (1995) article were based on appropriate data-analytic procedures because the primary concern is their investigation was the extent to which the patterns of T-score profiles from the original MMPI and the MMPI-2 are comparable when the raw-score patterns are virtually identical.     

Comparability of MMPI and MMPI-2 Profile Patterns: Ben-Porath and Tellegen's Inappropriate Invocation of Mahalanobis's D² Function

Ben-Porath and Tellegen (1995) claimed that the data in the article by Humphrey and Dahlstrom (1995) were improperly analyzed by means of Q correlations between raw scores earned by the individuals in the forensic sample to establish pattern comparability between the original Minnesota Multiphasic Personality Inventory (MMPI; Hathaway & McKinley, 1943) and the Minnesota Multiphasic Personality Inventory-2 (MMPI-2; Butcher, Dahlstrom, Graham, Tellegen, & Kaemmer, 1989), which were then contrasted with Q correlations between the corresponding T-score patterns. Ben-Porath and Tellegen (1995) contended that the Q correlation is affected by random factors and that a generalized distance function, D², is the only legitimate index of profile comparability. Data are presented here to show that the Q correlation serves as a reliable index of pattern comparability, relatively unaffected by differences in profile elevation. The Mahalanobis (1936) D² index is too heavily weighted with differences in profile elevation serve as the proper index of equivalence in profile patterning. The findings in the Humphrey and Dahlstrom (1995) article were based on appropriate data-analytic procedures because the primary concern is their investigation was the extent to which the patterns of T-score profiles from the original MMPI and the MMPI-2 are comparable when the raw-score patterns are virtually identical.     

Comparison of two methods of MMPI-2 profile classification

The present study investigated the extent of agreement of the highest scale method and the best-fit method in matching MMPI-2 profiles to database code-type profiles and considered profile characteristics that may relate to agreement or disagreement of code-type matches by these two methods. A sample of 519 MMPI-2 profiles that had been classified into database profile code types by these two methods was studied. Resulting code-type matches were classified into three groups: identical (30%), similar (39%), and different (31%), and the profile characteristics of profile elevation, dispersion, and profile code-type definition were studied. Profile code-type definition was significantly different across the three groups with identical and similar match profile groups showing greater profile code-type definition and the different group consisting of profiles that were less well-defined.     

Similarities and differences between MMPI and MMPI-2 applications to the assessment of posttraumatic stress disorder

The purpose of this study was to address the question: Is the Minnesota Multiphasic Personality Inventory-2 (MMPI-2) comparable to the original MMPI in its applicability to the assessment of posttraumatic stress disorder (PTSD) among Vietnam combat veterans? The question was addressed by administering both the original MMPI and MMPI-2 to 29 subjects classified as meeting Diagnostic and Statistical Manual of Mental Disorders (3rd ed., rev.; DSM-III-R) criteria for PTSD and comparing MMPI and MMPI-2 scores in terms of: degree of association, code-type congruence, diagnostic hit rates (when compared to two other clinical samples, and one normal sample), and congruence of the Keane PTSD Scale (PK). Results reveal highly significant correlations between MMPI and MMPI-2 basic scales for the PTSD sample as well as congruence in 2-point codes comparable to previous studies. The MMPI-2 was found to identify effectively PTSD subjects from the other groups. Results also showed a high degree of association between the MMPI and MMPI-2 in regard to PK scores, although minor differences were found in PK raw scores between the two tests. Overall, the findings suggest a high degree of comparability between the MMPI and MMPI-2 in the assessment of PTSD.     

Comparison of MMPI-2 and MMPI Clinical Scales and High-Point Scores Among Methadone Maintenance Clients

Methadone client volunteers completed the Minnesota Multiphasic Personality Inventory (MMPI; Hathaway & McKinley, 1967) and MMPI-2 (Butcher, Dahlstrom, Graham, Tellegen, & Kaemmer, 1989) on consecutive days. MMPI2 T-scores were lower by a mean of 4.7 on the clinical scales; when 5 points were added to MMPI-2 T-scores the mean difference was 2.3. Rank order of subjects on scale T-scores was not significantly different between the two instruments. High-point similarity for clinically elevated profile pairs ranged from 61% to 92%, depending upon definition of similarity.     

Comparability of Two-Point High-Point Code Patterns From Original MMPI Norms to MMPI-2 Norms for the Restandardization Sample

Using records from the 1,138 males and 1,462 females in the Minnesota Multiphasic Personality Inventory-2 (MMPI-2) restandardization sample (Butcher, Dahlstrom, Graham, Tellegen, & Kaemmer, 1989), two-point high-point code patterns generated from the original norms were compared to the patterns that these subjects obtained from the new norms. Although some code patterns proved to be quite stable across both norms, code comparability was generally lower in this community-based sample than was true for the records from samples of psychiatric patients also reported in Butcher et al. (1989). The sources of differences between the original and the new norms were reviewed, and the implications for profile interpretation based on code patterns were pointed out. The differences arising from the use of the MMPI-2 norms are appreciable; they highlight the need for new empirical data on the correlates of coding patterns based on these norms.     

Comparability of two-point high-point code patterns from original MMPI norms to MMPI-2 norms for the restandardization sample

Using records from the 1,138 males and 1,462 females in the Minnesota Multiphasic Personality Inventory-2 (MMPI-2) restandardization sample (Butcher, Dahlstrom, Graham, Tellegen, & Kaemmer, 1989), two-point high-point code patterns generated from the original norms were compared to the patterns that these subjects obtained from the new norms. Although some code patterns proved to be quite stable across both norms, code comparability was generally lower in this community-based sample than was true for the records from samples of psychiatric patients also reported in Butcher et al. (1989). The sources of differences between the original and the new norms were reviewed, and the implications for profile interpretation based on code patterns were pointed out. The differences arising from the use of the MMPI-2 norms are appreciable; they highlight the need for new empirical data on the correlates of coding patterns based on these norms.     

Assessing depression with the MMPI and MMPI-2

The usefulness of the MMPI (Hathaway & McKinley, 1951 ) and MMPI-2 (Butcher, Dahlstrom, Graham, Tellegen, & Kaemmer, 1989) for diagnosing and assessing symptomatic depression has been the subject of considerable debate for a number of years. In this article, we review the relative contributions of the MMPI and MMPI-2 clinical and content scales in predicting depression. Positive predictive power, negative predictive power, and overall classification rate were computed for Scale 2 (D) of the MMPI and MMPI-2 and the Depression content scale (DEP) of the MMPI-2. Scale 2 (D) of both the MMPI and MMPI-2 appears to be moderately accurate in predicting depression. Although some studies suggest that the content scale DEP provides incremental validity over Scale 2 (D) of the MMPI-2, the results of this review indicate that the content scale DEP of the MMPI-2 does not exceed the diagnostic efficiency of Scale 2 in predicting depression.     

MMPI-2 profiles of women with eating disorders in a Dutch day treatment sample

In this study, we examined the MMPI-2 (Butcher, Dahlstrom, Graham, Tellegen, & Kaemmer, 1989) profiles of 324 Dutch patients with eating disorders at an eating disorder day treatment program. We studied the MMPI-2 profiles in 5 diagnostic eating disorder groups. All diagnostic subgroups showed high mean elevations of the T scores on the same 6 or 7 scales. Remarkable similarities existed between the mean profile configurations. The MMPI-2 distinguished especially in that patients with restricting anorexia nervosa scored lower on one Validity scale (F), two Clinical scales (1 and 2) and several Supplementary and Content scales of the MMPI-2 compared to the other groups. Only on the validity Scale L did they score higher. The MMPI-2 also distinguished patients with the bulimia nervosa purging type who scored higher on Scale 9 and different on several Content and Supplementary scales. We discuss results with regard to other studies of MMPI (Hathaway & McKinley, 1983) and MMPI-2 profiles of women with anorexia nervosa, bulimia nervosa, and eating disorder not otherwise specified in inpatient and outpatient settings.     

MMPI-2 in the inpatient assessment of women with eating disorders

The MMPI-2 (Butcher, Dahlstrom, Graham, Tellegen, & Kaemmer, 1989) reveals similar patterns across all Diagnostic and Statistical Manual of Mental Disorders (4th ed.; American Psychiatric Association, 1994) eating-disorder diagnoses. In this study, 550 women with eating disorders completed the MMPI-2. The 3 highest mean elevations for all eating-disorder diagnostic groups occurred on the same scales in the same order: 2, 7, and 3. The modal code for all groups was 2-7/7-2. However, multivariate analyses using the 16 validity and clinical scales, as well as the 27 content and supplementary scales, indicated that the MMPI-2 also distinguishes among eating disorders, especially in that patients with restricting anorexia report less psychopathology than other groups. These results are compared with the results of past eating-disorder research that used the older MMPI (Hathaway & McKinley, 1983).     

Comparability of MMPI-2 scales and profiles over time

This study investigated Minnesota Multiphasic Personality Inventory-2 (MMPI-2; Butcher, Dahlstrom, Graham, Tellegen, & Kaemmer, 1989) scale and profile comparablilty for MMPI-2 profiles completed on 2 separate occasions by mental health patients receiving treatment at a Veterans Affairs Medical Center (n = 114). Patients were predominantly men (96.5%), with an average age of 44.08 and an average of 12.39 years of education at the time of initial testing. MMPI-2 tests were completed on 2 separate occasions as a routine part of treatment with a mean interval between test administrations of 688 days. Findings were analyzed for the complete sample and for 3 subsamples with different test-retest intervals. MMPI-2 scale test-retest correlation coefficients for the entire sample ranged from .48 to .69 for the Basic scales, .49 to .80 for the Supplementary scales, and .56 to .78 for the Content scales with scale high-point agreement = 38.60%, high 2-point agreement = 16.67%, and high 3-point agreement = 19.30%. High-point agreement for subsets of participants with well-defined high points, 2-points and 3-points was 41.07%, 27.50%, and 25.93% respectively. Pearson r correlation coefficients for T scores across the Basic scales for pairs of profiles averaged .78, suggesting similarity of profile shape across testing occasions. MMPI-2 profiles were also examined in relation to Skinner and Jackson's 3 modal MMPI profile types.     

MMPI-2 profile code types and measurement error

We studied simulated MMPI-2 (Butcher, Dahlstrom, Graham, Tellegen, & Kaemmer, 1989) code type stability and change expected with measurement error for 12 MMPI-2 well-defined mean code type profiles. Profile scores for the 2 scales defining the code type were systematically varied to represent target code type profiles at 9 different levels of T-score profile definition. We randomly generated samples of 50 simulated, estimated true score profiles at each level of profile definition for each code type around the estimated true scores for each scale at each level of profile definition. Two sets of simulated profiles were developed. The first simulation was based on the reported means, test-retest reliabilities, and the standard errors of measurement for the MMPI-2 normative group. The second simulation was based on the means, standard deviations, and estimated retest stability for a clinical group of psychiatric patients. We calculated frequencies and percentages of simulated profiles with the highest estimated true scores on the same 2 scales as the original code type profile. Percentages of simulated profiles with the same 2 highest scales as the original code type profiles increased from 27% to 37% for the 3-point level of definition, 37% to 49% for the 5-point definition, 46% to 61% for 7-point definition, 63% to 78% for 10-point definition, 78% to 89% for 13-point definition, 83% to 93% for 15-point definition, and greater than 90% for profile definition greater than 15 points.     

Psychometric characteristics of the MMPI-2 Cook-Medley Hostility scale

The Minnesota Multiphasic Personality Inventory (MMPI; Hathaway & McKinley, 1943) Cook-Medley Hostility scale (Ho) has been studied a great deal because of its relation to coronary disease and mortality. However, little research has been conducted with the Ho scale on the revised MMPI (MMPI-2; Butcher, Dahlstrom, Graham, Tellegen, & Kaemmer, 1989). This study examined the psychometric characteristics of the MMPI-2 Ho scale. Only nine of the original 50 Ho items were slightly changed in the revision. Ho scores were highly correlated with MMPI-2 scales CYN, K, TPA, and ASP, supporting the interpretation of Ho as a measure of cynicism. High correlations with other MMPI-2 scales also suggested that Ho is related to general psychopathology and negative affectivity. Male Ho scorers were rated by their spouses as hotheaded, bossy, demanding, and argumentative. For women, Ho scale scores were less strongly associated with ratings of overt hostility. Principal components analysis of Ho revealed four underlying dimensions: Cynicism, Hypersensitivity, Aggressive Responding, and Social Avoidance.