Patient-reported outcomes (PRO) come directly from a patient about their health condition or impact of its treatments without interpretation by health care providers. Measures of disease activity in ulcerative colitis (UC) traditionally have included a combination of PROs (rectal bleeding [RB] and stool frequency [SF]), physician-assessed patient-based outcomes (physician global assessment), and objective measures of disease activity (endoscopic mucosal healing [MH]). These often are assessed using the Mayo score, and have formed the basis of all phase 3 clinical trial end points for drug approval and labeling claims.