Psychometric characteristics of a brief measure of pain-related functional impairment.

This study presents reliability and validity data from two samples (pain clinic vs medical clinic) on a five-item self-report scale, termed the Functional Interference Estimate (FIE), designed to measure functional impairment associated with chronic pain. Results from the pain clinic sample demonstrated that the FIE is internally consistent and has satisfactory levels of test-retest reliability, item-total score correlations, and convergent validity. Results from the medical clinic sample demonstrated that the FIE discriminated between medical clinic patients without pain and both medical clinic patients with pain and pain clinic patients. The data support the use of the FIE as one of several available assessment methods for evaluation of pain-related functional impairment.