Comparison of Adenoma Detection Miss Rates at Colonoscopy Associated With Different Withdrawal Times

The objective of this study is to determine the optimal withdrawal time for colonoscopy. A 6-minute withdrawal time is currently the standard of care but has only been evaluated in an observational fashion. The investigators believe that this should be validated in a standardized fashion. If the benefits of a 6 minute withdrawal are proven in this study (ie a low polyp/adenoma miss rate and a high polyp/adenoma detection rate), then this will support widespread adoption of a 6 minute withdrawal as the standard of care. This in turn may decrease the occurence of \'interval colon cancers\', which are early colon cancers arising in subjects despite their having undergone colonoscopy. Our hypothesis is that the polyp/adenoma detection rate will be unacceptably low and the polyp/adenoma miss rate will be unacceptably high in the 3-minute withdrawal group when compared to the 6-minute withdrawal group.