Inclusion Criteria:  Gastrointestinal (GI) patients with an outpatient appointment in the gastroenterology department for an endoscopic procedure in the context of the Dutch national screening program, because of gastrointestinal symptoms, or because of follow-up of previously diagnosed bowel diseases (in one of the two participating hospitals); Gastroenterologists working in Dutch hospitals; Gastroenterology fellows working in Dutch hospitals; Minimal age of 18 years old.  Exclusion Criteria:  No appropriate understanding of the Dutch language; Not willing to sign informed consent; Objection to participate in medical scientific research, reported in the medical file.