<qa>  What is the foundation for effective and high quality training?Teaching colonoscopy is difficult and time consuming. Most experienced colonoscopists are unable to give detailed guidance without actually taking over the procedure from the trainee as their perform-ance of colonoscopy has become largely automated or unconsciously competent over the years. It follows that a necessary foundation for effective and high quality training is a faculty of trainers experienced colonoscopists who have themselves received training as trainers, are aware of the quality of their own performance, and agree on the criteria for a high quality colonoscopy. 