Previous published audits and studies comparing different types of colon cleansing preparations have been limited by small sample size with only 5 published papers having over 100 patients in each arm of the study. These 5 studies suggest that NaP may be better than PEG but the recent meta-analysis failed to show this, primarily due to the large number of smaller studies showing PEG was better than NaP. Interpretation of the studies is limited by inconsistent and poorly defined measures of efficacy outcome. Most studies have used a subjective endoscopists assessment of the overall quality of the bowel preparation making comparisons between studies impossible. Recently a calibrated externally validated outcome assessment tool has been developed to objectively quantify the quality of bowel preparation4, but no randomised published study has yet utilised this tool.