Objectives: The objective of this study was to demonstrate through a case study how an analysis of means (ANOM) chart can be used to compare groups and to advocate the usefulness of this method in improvement work.
Methods: The ANOM technique was used to compare referral rates among providers at the Dartmouth-Hitchcock Medical Center's Spine Center. The purpose was to see whether there were any differences across providers in referral rates to Behavioral Medicine services for patients who scored low on their mental health score and whether referral rates were any different among the patient characteristics. ANOM charts were also used to determine whether patient characteristics were different among the providers.
Results: Six of the 17 providers had significantly different referral rates compared to the overall referral rate of 38%. Seven patients' characteristics had a significantly different referral rate compared to the system's rate. The additional ANOM charts used to compare providers relative to specific patient characteristics demonstrated several special causes and revealed characteristic referral patterns for some of the providers analyzed.
Conclusion: The ANOM chart may be underutilized in health care improvement work. The ANOM procedure of analyzing patient characteristics to determine differences among providers could be explored in other patient populations and settings.