The methodology and results of a recent investigation by Louks, Freeman, and Calsyn (1978) are reviewed. It is demonstrated that the results may have been confounded by inappropriate experimental procedures. Regardless of the methodological deficiencies associated with the experimental procedures, the results do not provide adequate support for the continued differentiation of individual low back pain patients with respect to the etiology of their pain. It is suggested that psychologists may best contribute to the assessment and treatment of individual pain patients by developing actuarial rules regarding the pain-related behavioral characteristics shared by members of various patient subgroups and the specific treatments to which subgroup members best respond. © 1978, Taylor & Francis Group, LLC. All rights reserved.