Thomsen, Lisa (2008) Determining MMPI-2 Protocol Validity: NVI, a Composite Measure to Assess Negative Response Bias. Honours thesis, University of Southern Queensland. (Unpublished)
Abstract
The MMPI-2 is regarded by many as the current leading test of individual psychosocial functioning. Being a self-report test, correct interpretation depends primarily on the genuineness with which the testtaker responds to items within it. In the setting of personal injury and disability claims, individuals may attempt to “fake bad” on the MMPI-2, in order to convey a more negative level of functioning, with base rates of symptom overreporting in this arena having been reported to be around 30%. When tests such as the MMPI-2 are used in medicolegal settings, it is therefore essential to ensure that validity measures exist which can effectively and accurately discriminate between genuine and exaggerated protocols. There are numerous measures available to identify negative impression management on the MMPI-2, however no clear consensus exists as to which is the most effective. The 2002 Meyers Index was created in the belief that a composite validity index would best be able to correctly identify protocol exaggeration, however some of the measures within it have become redundant, and other new and promising scales have since emerged. The Meyers Index is therefore no longer a viable option for the clinician, suggesting the necessity of creating an updated multiple scale validity measure to assess exaggerated symptomology on the MMPI-2. As such, the purpose of this study was to create a new MMPI-2 composite measure of negative response bias, the Negative Validity Index (NVI). Each validity scale eligible for inclusion was examined to determine suitability on the basis of reliability, construct validity, redundancy, content validity and pragmatic considerations. A research review illustrated previous performance across settings, and then statistical analyses were performed to aid in the selection of scales for inclusion in the NVI. A principal component analysis determined the number of underlying factors measured by the various validity scales, and the construction of the NVI ensured that all identified components were represented. The degree of interrelatedness between scales was assessed through the calculation of correlations, with the intention of reducing NVI redundancy through the selection of scales with minimal item overlap. Multiple regressions were performed to identify which MMPI-2 clinical and content scales predicted the elevation of each validity scale, and the combination of scales selected for the NVI was balanced to prevent against differential vulnerabilities to clinical issues. Finally, internal consistencies were calculated to ensure that all included scales were reliable. Following these analyses, it was determined that the ultimate combination of validity scales for the NVI consisted of eight measures, namely FBS, Mmds, HHI, F, Fb, Dsr-2, and Fp, which together demonstrated an internal consistency coefficient of .87. A correlation of .91 was calculated between the NVI and the Meyers Index. Preliminary validation of the NVI was conducted by comparing its performance with that of the Meyers Index. A comparison of frequency distributions on a sample of personal injury and disability claimants, revealed a comparable 29% of protocols identified as exaggerated by the Meyers Index, and 24% identified by the NVI, which is within expected base rates. Until further validation occurs a cut score of 7 on the NVI would conservatively estimate 20% of the sample as exaggerating, with a demonstrated overall accuracy within this sample of 91.4%. Further studies are necessary to determine the effectiveness of the NVI, especially where performance is not based on existing MMPI-2 validity scales, however initial exploration of the NVI is encouraging in regards to the promise it shows in the ability to identify negative response bias on the MMPI-2, especially given the importance of accurate validity testing.
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| Item Type: | Thesis (Non-Research) (Honours) |
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| Item Status: | Live Archive |
| Additional Information: | Current UniSQ staff and students can request access to this thesis. Please email research.repository@unisq.edu.au with a subject line of SEAR thesis request and provide: Name of the thesis requested and Your name and UniSQ email address |
| Faculty/School / Institute/Centre: | Historic - Faculty of Sciences - Department of Psychology (Up to 30 Jun 2013) |
| Supervisors: | Graeme Senior |
| Qualification: | Bachelor of Science (Honours) |
| Date Deposited: | 13 Nov 2025 01:39 |
| Last Modified: | 13 Nov 2025 01:39 |
| Fields of Research (2008): | 17 Psychology and Cognitive Sciences > 1799 Other Psychology and Cognitive Sciences > 179999 Psychology and Cognitive Sciences not elsewhere classified |
| Fields of Research (2020): | 52 PSYCHOLOGY > 5299 Other psychology > 529999 Other psychology not elsewhere classified |
| URI: | https://sear.unisq.edu.au/id/eprint/52820 |
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