Measurements
A questionnaire was filled out by each subject immediately before the colonoscopy is provided in Additional file A questionnaire was filled out by the gastroenterologist immediately after the colonoscopy rating the cleanliness of the bowel preparation and is provided in Additional file A primary endpoint of this study (Table The Chicago Bowel Preparation Scale [Secondary end points of the study were the tolerance of high-dose bowel preparations determined from the subject questionnaire, cleanliness of the colon on the Boston Preparation Scale [400 subjects from arm 2 (357 g of PEG and Gatorade given the day-prior) and arm 3 (306 g of PEG and Gatorade given as a split-dose) of a previous colon cleansing study [Before the study began, each participating gastroenterologist watched a video (domweb.bumc.bu.edu/bowelprep/instruction.php) as a calibration exercise for both the Chicago BPS and Boston BPS with the results discussed among the authors.