The subjective experience of acute pain. An assessment of the utility of 10 indices.

Sixty-nine postoperative patients indicated the severity of their pain using eight measures designed to assess pain intensity and two designed to measure pain affect. The utility and validity of the 10 measures were evaluated according to two criteria: (a) the magnitude of the relationship between each scale and a linear combination of the pain measures, and (b) relative rates of incorrect responding. The results indicate that each of the measures of pain intensity is adequately valid. In addition, this sample of patients failed to differentiate pain intensity and pain affect using the present measures, suggesting the need for additional research to explore the validity of the affective measures employed in the study. The 11-point Box Scale (BS-11) of pain intensity demonstrated the strongest relationship to a linear combination of all of the measures employed and was responded to correctly by each subject in the sample. All else being equal, these results suggest that the BS-11 scale may be the most useful clinical index of pain intensity among postoperative patients.