A comparison of pain rating scales by sampling from clinical trial data

Clin J Pain. 2000 Mar;16(1):22-8. doi: 10.1097/00002508-200003000-00005.


Objective: The goals of this study were to examine agreement and estimate differences in sensitivity between pain assessment scales.

Design: Multiple simultaneous pain assessments by patients in acute pain after oral surgery were used to compare a four-category verbal rating scale (VRS-4) and an 11-point numeric rating scale (NRS-11) with a 100-mm visual analog scale (VAS). The sensitivity of the scales (i.e., their ability [power] to detect differences between treatments) was compared in a simulation model by sampling from true pairs of observations using varying treatment differences of predetermined size.

Results: There was considerable variability in VAS scores within each VRS-4 or NRS-11 category both between patients and for repeated measures from the same patient. Simulation experiments showed that the VAS was systematically more powerful than the VRS-4 in all simulations performed. The sensitivity of the VAS and NRS-11 was approximately equal.

Conclusions: In this acute pain model, the VRS-4 was less sensitive than the VAS. The simulation results demonstrated similar sensitivity of the NRS-11 and VAS when comparing acute postoperative pain intensity. The choice between the VAS and NRS-11 can thus be based on subjective preferences.

Publication types

  • Clinical Trial
  • Comparative Study
  • Randomized Controlled Trial

MeSH terms

  • Double-Blind Method
  • Humans
  • Pain Measurement / methods*
  • Pain Measurement / standards*
  • Pain, Postoperative / physiopathology
  • Reproducibility of Results
  • Sensitivity and Specificity
  • Stochastic Processes
  • Surgery, Oral