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Psychometric Considerations of the MMPI-2

Psychometric Considerations of the MMPI-2. William P. Wattles, Ph.D. Francis Marion University. MMPI/MMPI-2 second most widely used test by clincical psychologists (86%) Translated into more than 50 languages. Original MMPI. Published 1943

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Psychometric Considerations of the MMPI-2

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  1. Psychometric Considerations of the MMPI-2 William P. Wattles, Ph.D. Francis Marion University

  2. MMPI/MMPI-2 second most widely used test by clincical psychologists (86%) • Translated into more than 50 languages

  3. Original MMPI • Published 1943 • Paper and pencil improvement on clinical interview and individual psychological testing

  4. Prior to MMPI: Logical Keying • Test items generated rationally based on: • Face validity • Subjective judgment • Logically keyed items problematic: • Subject to faking • Not always correct

  5. Face Validity • Does the test appear to measure what it is purported to Measure?

  6. Face Validity 0 I do not feel sad. 1 I feel sad. 2 I am sad all the time and can't snap out of it. 3 I am so sad or unhappy that I can't stand it.

  7. 70. I am easily downed in an argument • 89 My hardest values are with myself • 267 I have periods in which I feel unusually cheerful without any special reason. • 219 I have been disappointed in love

  8. Empirical Keying • Original items came from many sources. • Pool of 1,000 items reduced to 566 • Rewritten to be less formal and allow for some reversal of responses.

  9. Control Group • 724 Visitors to the hospital in Minnesota. • Representative of Minnesota in the 1930s • 16-65 • Average age mind 30’s • Rural • 8th grade education • White

  10. Empirical Keying • Using groups of diagnosed patients • Contrast and Cross-validation

  11. MMPI vs MMPI 2 • Improved norms • Score has meaning only when compared to a representative sample. • Original sample Caucasian, 35, married, small town, good job. • New sample large and more representative. • Higher education level than population

  12. MMPI-2 normative group • 2600 Participants • Paid $15 ($40 for couples) • Tested in 7 locations • Minnesota, Ohio, North Carolina, Washington, Pennsylvania, Virginia, California • Selected from phone directories

  13. MMPI-2 composition • 2600 Participants (started with 2900) • 1138 men • 1462 women • Age 18-85 (M=41, SD=15) • 61% married • Education 3-20 years (M=14, SD=2)

  14. MMPI-2 Restandardization • Caucasian 81% • African-American 12% • Hispanic 3% • Native-American 3% • Asian-American 1%

  15. Requirements • Eight Grade reading level required • Satisfactory cooperation and commitment to task • Internal checks for the above

  16. T Score transformations • Transforming a score makes it easier to interpret. • 13 validity and clinical scales converted to T scores • T score is a standard score with a mean of 50 and a standard deviation of 10. • Thus, a 70 is like a Z score of 2

  17. Standard Scores or Z scores • Z score: how many standard deviations a score lies above or below the mean.

  18. 68% 95% 99.7% 46

  19. Percent of scores falling below

  20. 99.85% 97.5% 84% 46

  21. Z-score 33

  22. MMPI-2 T score 33

  23. Original linear T-scores were problematic because the underlying data is somewhat skewed. Thus a T score on one scale represented a different percentile than one on another scale MMPI Uniform T score

  24. Involve averaging of the T-scores across the scales. MMPI Uniform T-scores

  25. Frequency high points in contemporary settings

  26. T-score cutoff • Formerly T-scores of 70 were considered clinically significant. Now the MMPI-2 recommends 65. • That puts the score above 93% of those who answer • 65-50/10 = 1.5 • 1.5 = .9332 area under standard normal curve to the left of Z = 1.5

  27. Intercorrelations • There is considerable overlap between some scales. 13 of 39 items in scale 6 also appear in scale 8

  28. Homogeneity of items • The empirical keying approach did not favor item homogeneity thus internal consistency is not high.

  29. Temporal Stability • Ability, interest and aptitude tests should be high in temporal stability • Personality and psychopathology measures less clear.

  30. Test-retest reliability one week

  31. Test-retest reliability • Summary. Test is fairly stable and changes when current appear consistent. Significant changes generally correctly reflect behavior change.

  32. Internal consistency • Moderate, not a strength for the MMPI-2 due to empirical keying approach.

  33. Factor Analysis • Two strong factors identified • General maladjustment and psychotic thought • Neurotic characteristics

  34. Response sets and styles • Charges that MMPI and MMPI-2 were confounded by response style. • Block modified MMPI to have equal number of true and false items • Test seems to be valid in a variety of settings.

  35. MMPI vs MMPI-2 • Validity similar • Raw Scores higher on MMPI-2 • May be explained by instructions • T-scores compensate for higher raw scores

  36. Items changed MMPI-2

  37. Basic Qualifications for users • Graduate-level course in psychological testing. • Standard scores • Transformations • Understand limits of accuracy • Standard error of measurement

  38. Basic Qualifications for users • Graduate-level course in psychopathology • Personality structure • Dynamics • Deviance psychodiagnostic concepts • Diagnostic systems • Broad understanding of human personality

  39. Lexile Reading Levels in SIRS Lexile Score Table from www.lexile.com: What Are Lexile Reading Levels • Lexile scores match reader ability and text difficulty, allowing individualized monitoring of student progress. • Due to the accountability requirements of NCLB, many states are turning to standardized systems for reading which help to track student progress. How does it Work? • Lexile measures are based on two well-established predictors of how difficult a text is to comprehend: semantic difficulty (word frequency) and syntactic complexity (sentence length).

  40. Reading Level

  41. Lexile examples • 39 I am an important person • 294 I have not lived the right kind of life • 603 I do not read every editorial in the newspaper everyday • 860 Most anytime I would rather sit and daydream than do anything else. • 1042 I am troubled by discomfort in the pit of my stomach every few days or oftener.

  42. Testing conditions • Quiet room one setting preferred • Okay to take over several intervals • Person must have privacy and no help • Simple definitions of words permitted along with rephrasing of colloquialisms • Usually sufficient to say: “Just indicate the way you see it.”

  43. Examiner to act in a serious and professional manner • Don’t linger too long in one area

  44. The End The End

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