Flug JA, et al. - Researchers planned this study to analyze trends in exclusion criteria coding over time by the site of service after implementation of OP-8 to evaluate provider’s response to public reporting. For outpatient hospitals and clinics, documentation of excluding conditions and other clinically reasonable exclusions for OP-8 increased over time. Increases in the documentation of comorbidities could not translate to actual improvement in imaging appropriateness for low back pain. The proportion of patients with low back pain considered uncomplicated and being measured by OP-8 would be small, reflecting a small proportion of patients with low back pain when accounting for all relevant conditions.