Clinical judgment is a process based on solid scientific knowledge and is characterized as being “systematic (i.e., organized, sequential, and logical), formal (i.e., explicit and reasoned), and transparent (i.e., apparent and communicated clearly)” (Schalock & Luckasson, 2005, p.1). The application of clinical judgment in the evaluation of IQ scores in the diagnosis of intellectual disability includes consideration of multiple factors that might influence the accuracy of an assessment of general intellectual ability (APA: DSM-5, 2013). The “unanimous professional consensus that the diagnosis of intellectual disability requires comprehensive assessment and the application of clinical judgment” (Brief of Amici Curiae American Psychological Association, American Psychiatric Association, American Academy of Psychiatry and the Law, Florida Psychological Association, National Association of Social Workers, and National Association of Social Workers Florida Chapter, in Support of Petitioner; Hall v. Florida; S.Ct., No. 12-10882; 2014; p. 8).
The misuse of clinical judgment in the interpretation of scores from intelligence test batteries should not be used as the basis for “gut instinct” or “seat-of-the-pants” impressions and conclusions of the assessment professional (Macvaugh & Cunningham, 2009), or justification for shortened evaluations, a means to convey stereotypes or prejudices, a substitute for insufficiently explored questions, or an excuse for incomplete testing and missing data (Schalock & Luckasson, 2005). Idiosyncratic methods and intuitive conclusions are not scientifically based and have unknown reliability and validity.
If clinical judgment interpretations and opinions regarding an individual’s level of general intelligence are based on novel or emerging research-based principles, the assessment professional must document the bases for these new interpretations as well as the limitations of these principles and methods. This requirement is consistent with the Standards for Educational and Psychological Testing Standard 9.4 which states:
When a test is to be used for a purpose for which little or no validity evidence is available, the user is responsible for documenting the rationale for the selection of the test and obtaining evidence of the reliability/precision of the test scores and the validity of the interpretations supporting the use of the scores for this purpose (p. 143).
American Educational Research Association, American Psychological Association, & National Council on Measurement in Education (2014). Standards for educational and psychological testing. Washington, DC: Author.
American Psychiatric Association (2013). Diagnostic and statistical manual of mental disorders— Fifth Edition. Washington D.C.: Author.
Brief of Amici Curiae American Psychological Association, American Psychiatric Association, American Academy of Psychiatry and the Law, Florida Psychological Association, National Association of Social Workers, and National Association of Social Workers Florida Chapter, in Support of Petitioner; Hall v. Florida; S.Ct., No. 12-10882; 2014; p. 8.
MacVaugh, G. S. & Cunningham, M. D. (2009). Atkins v. Virginia: Implications and recommendations for forensic practice. The Journal of Psychiatry and Law, 37, 131-187.
Schalock, R. L. & Luckasson, R. (2005). Clinical judgment. Washington, DC: American Association on Intellectual and Developmental Disabilities.
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Kevin S. McGrew, PhD.
Educational Psychologist
Director
Institute for Applied Psychometrics (IAP)
