Limitations of the Millon Behavioral Medicine Diagnostic (MBMD) with Bariatric Surgical Candidates

Background  In this paper, we critique the Millon Behavioral Medicine Diagnostic’s (MBMD) psychometric characteristics for use with bariatric surgery patients. Methods  The reliability data presented by the test authors in their manual were examined. Results  The results found 16 of 32 scales of have internal consistency reliability coefficients that do not meet minimal standards for use with bariatric populations. Of the remaining 16 scales, 13 do not have any compelling evidence that they are reliable. We suggest that if a test is not psychometrically reliable then its validity is called into question. Based on these data, 16 of the MBMD’s 32 scales have inadequate reliability and 13 are lacking evidence of reliability. We urge clinicians to carefully consider these findings and the implications for their work with bariatric surgery patients.