Will Rogers Paradox in Gastroenterology.

The use of various classifications to grade and differentiate appearances of digestive diseases has enhanced precision and provided better means for their clinical evaluation and comparison. Staging systems abound to classify erosive esophagitis, gastro-esophageal varices, upper gastrointestinal hemorrhage, histopathology of celiac disease, various types of gastrointestinal neoplasia, and colitis associated with Crohn's disease or ulcerative colitis. The present review serves to highlight how potential bias may become introduced when comparing clinical outcomes based on varying and continuously evolving staging systems of digestive diseases.