The development of a self-administered psychophysical scaling method: range effects.
101 subjects engaged in a self-administered cross-modal matching task to scale descriptors of pain intensity and unpleasantness. The correlation between the two responses was used to determine reliability (internal consistency). When r greater than or equal to 0.90 was set as a criterion about 3% of the subjects were unable to calibrate standard stimuli reliability, 6% were unable to calibrate intensity descriptors and 60% were unable to calibrate unpleasantness descriptors reliably. When the criterion reliability was set at r greater than or equal to 0.85 all subjects successfully scaled the intensity descriptors. Further relaxation of the criterion to r greater than or equal to 0.80 reduced the 'failure' rate for unpleasantness descriptors to 24%. These data compare favourably with other published results from non-chronic and chronic pain patients. The provision of a fixed reference value produced range effects in the resulting scale but do not severely attenuate the range of the scale as has been previously suggested. It is concluded that a self-administered version of the task is feasible. Reasons for the poor performance with the unpleasantness descriptors are discussed.
Morley
Stephen
S
Department of Psychiatry, University of Leeds, Leeds LS2 9LT U.K.
D000328:Adult; D005260:Female; D006801:Humans; D008297:Male; D010146:Pain / Q000523:psychology*; D012647:Self-Assessment; D013223:Statistics as Topic