Gracely's work is based on the idea that "You can't just do magnitude measures of pain and really get a lot of meaning out of it unless you anchor the judgment some way....Every word response is an anchor to a subjective level". ¹

His research is characterized by the use of multiple internal controls to test the validity of the assessor (the patient); the validity of the internal relationships of the ranking terms; and the sensitivity of the scale to changes under analgesia or other environmental influences. In the initial set of studies, volunteer subjects selected words from two randomly organized lists to describe two different types of noxious stimuli (electrical shock and cold press or); their verbal rankings were further assessed against their analog responses (handgrip and line length) to stimuli. This "cross-modality matching" was a cross-check of both the subjects and the method.

Differential Descriptor Scale.

Cross-modality matching of verbal descriptiors against noxious stimuli. From Richard Gracely, Ronald Budner, Patricia McGrath, and Marc Heft New methods of pain measurement and their application to control. International Dental Journal v. 28 (1978): 55, 59.