There are several available endoscopic scoring systems that are designed to assess disease activity in inflammatory bowel disease. The most widely known is the Mayo endoscopic subscore for ulcerative colitis. These schemas are not routinely used in clinical practice, largely due to their complexity or lack of granularity, although they are standard for outcomes measurement in large clinical trials. While some schemas have been validated using independent cohorts, there is high inherent interobserver variation. Furthermore, derivation of these scoring systems has been subject to selection bias and limited challenge bias.