Figure 3

RMDQ and back pain intensity by ICD-9-CM code stratified by site. a displays the baseline measure of back-related physical disability (the Roland-Morris disability questionnaire) and b displays the baseline measure of pain (a numerical rating scale of average back pain in past week), stratified by site and compared with primary diagnosis code for the index visit using ICD-9-CM. Each outcome by demographic boxplot displays the within-group mean (horizontal in the center of the box) +/- the within-group standard deviation (upper and lower edges of the box). The vertical lines display the within-group range of scores.