Exploring the Face Validity of the Pain Numeric Rating Scale among Healthcare Providers

BACKGROUND: Healthcare providers (HCPs) use the numeric rating scale (NRS) under the assumption that it provides reliable information from which to make decisions regarding analgesic administration. METHODS: We explored the face validity of the NRS using a prospective single-blinded observational design. Pre and post NRS scores were obtained from HCPs who submerged their hand in a bucket of ice water (pain stimulus). RESULTS: Despite a consistent similar pain source, individual HCPs rated their pain very differently (range, 2-10), and there was a significant difference in self-estimated pain tolerance (μ = 7.06 [SD, 1.43]) and actual pain scores (μ = 6.35 [SD, 2.2]; t = 4.08, P <.001). CONCLUSION: The findings indicate a limitation in the face validity of the NRS. The high variance in NRS scores reaffirms the subjectivity of pain perception and brings into question the utility of using NRS scores when determining analgesic dosages.