Researchers at the Betsy Lehman Center found considerable variability across health care facilities when trying to assess the frequency of patient harm after gastrointestinal (GI) endoscopies performed in outpatient hospital settings and ambulatory surgery centers in the state. An analysis of claims data showed that unplanned hospital visits by patients within 7 days of their screening colonoscopies ranged from 5.6 to 26.2 per 1000 procedures. Variation was even more pronounced for non-screening colonoscopies (4.9 to 49.5 per 1000) and esophagogastroduodenoscopies (13.2 to 112.3 per 1000). The analysis also showed that GI endoscopy patients experienced fewer unplanned hospital encounters within 7 and 30 days of their procedures at ASCs compared to hospital outpatient centers, after risk-adjustment. A limitation of the study is that claims data cannot discern reasons for the differences, which could range from sedation and procedure-characteristics to patients’ overall general health before the procedure.