 Computer assisted instruction As intervention an interactive CAI was designed, according to current best practices, like good accessibility, plain language and engaging the user. Therefore the information was presented stepwise. The CAI consisted of a web-based platform using video mimicking the patient journey with voice-over supported by photos, 3D animation and instructive texts. The video was presented in short clips, maximal 45 seconds, to maintain the focus of patient. Patient interaction was ascertained by mandatory mouse-click after each item in the CAI. All informative elements, especially mandatory for informed consent for colonoscopy risks, alternatives were included. 