Reviewer's report 
 Comparison of Morning versus Afternoon Cecal Intubation Rates Title: 
 1  23 February 2007 Version: Date: 
 George Dafnis Reviewer: 
Reviewer's report: 
General 
This is a well written study comprising a large number of colonoscopies. It highlights the importance of 
proper bowel preparation and the impact on completion rates. I have some minor suggestions that I think the authors should address. 
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Major Compulsory Revisions (that the author must respond to before a decision on publication can be reached) 
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Minor Essential Revisions (such as missing labels on figures, or the wrong use of a term, which the author can be trusted to correct) 
1. Presence of diverticulosis has been shown to be associated with lower completion rates. Data on this is 
not mentioned in your paper. Have you controlled for this variable in the logistic regression analysis? 
2. What criteria were used to define if the cecum was reached? 
3. You mention that the endoscopist is a variable in the analysis. How do 
you characterize the skill of the endoscopist? Number of colonoscopies performed? Number of years as an endoscopist? I think this should be stated in the methods paragraph. This may influence the results of the 
study. 
4. Results, paragraph 2: “were observed in 94.5% of patients in the AM group versus 90.2% in 9.8% in the 
PM group………” 
This should be: “were observed in 94.5% of patients in the AM group versus 
90.2% in the PM group………” 
5. As the authors point out themselves in 63% of the incomplete examinations the reason for an incomplete 
examination is not stated. Thus in 211 colonoscopies the reason for incompletion is unknown. It would have been interesting to know why the cecum was not reached. 
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Discretionary Revisions (which the author can choose to ignore) 
 Accept after minor essential revisions What next?: 
 An article whose findings are important to those with closely related research interests Level of interest: 
 Acceptable Quality of written English: 
 No, the manuscript does not need to be seen by a statistician. Statistical review: 
Declaration of competing interests: 
I declare that I have no competing interests 
Reviewer's report 
 Comparison of Morning versus Afternoon Cecal Intubation Rates Title: 
 1  23 February 2007 Version: Date: 
 George Dafnis Reviewer: 
Reviewer's report: 
General 
This is a well written study comprising a large number of colonoscopies. It highlights the importance of 
proper bowel preparation and the impact on completion rates. I have some minor suggestions that I think the authors should address. 
------------------------------------------------------------------------------- 
Major Compulsory Revisions (that the author must respond to before a decision on publication can be reached) 
------------------------------------------------------------------------------- 
Minor Essential Revisions (such as missing labels on figures, or the wrong use of a term, which the author can be trusted to correct) 
1. Presence of diverticulosis has been shown to be associated with lower completion rates. Data on this is 
not mentioned in your paper. Have you controlled for this variable in the logistic regression analysis? 
2. What criteria were used to define if the cecum was reached? 
3. You mention that the endoscopist is a variable in the analysis. How do 
you characterize the skill of the endoscopist? Number of colonoscopies performed? Number of years as an endoscopist? I think this should be stated in the methods paragraph. This may influence the results of the 
study. 
4. Results, paragraph 2: “were observed in 94.5% of patients in the AM group versus 90.2% in 9.8% in the 
PM group………” 
This should be: “were observed in 94.5% of patients in the AM group versus 
90.2% in the PM group………” 
5. As the authors point out themselves in 63% of the incomplete examinations the reason for an incomplete 
examination is not stated. Thus in 211 colonoscopies the reason for incompletion is unknown. It would have been interesting to know why the cecum was not reached. 
------------------------------------------------------------------------------- 
Discretionary Revisions (which the author can choose to ignore) 
 Accept after minor essential revisions What next?: 
 An article whose findings are important to those with closely related research interests Level of interest: 
 Acceptable Quality of written English: 
 No, the manuscript does not need to be seen by a statistician. Statistical review: 
Declaration of competing interests: 
I declare that I have no competing interests 
Please review this paper.
user
Reviewer's report 
 Comparison of Morning versus Afternoon Cecal Intubation Rates Title: 
 1  23 February 2007 Version: Date: 
 George Dafnis Reviewer: 
Reviewer's report: 
General 
This is a well written study comprising a large number of colonoscopies. It highlights the importance of 
proper bowel preparation and the impact on completion rates. I have some minor suggestions that I think the authors should address. 
------------------------------------------------------------------------------- 
Major Compulsory Revisions (that the author must respond to before a decision on publication can be reached) 
------------------------------------------------------------------------------- 
Minor Essential Revisions (such as missing labels on figures, or the wrong use of a term, which the author can be trusted to correct) 
1. Presence of diverticulosis has been shown to be associated with lower completion rates. Data on this is 
not mentioned in your paper. Have you controlled for this variable in the logistic regression analysis? 
2. What criteria were used to define if the cecum was reached? 
3. You mention that the endoscopist is a variable in the analysis. How do 
you characterize the skill of the endoscopist? Number of colonoscopies performed? Number of years as an endoscopist? I think this should be stated in the methods paragraph. This may influence the results of the 
study. 
4. Results, paragraph 2: “were observed in 94.5% of patients in the AM group versus 90.2% in 9.8% in the 
PM group………” 
This should be: “were observed in 94.5% of patients in the AM group versus 
90.2% in the PM group………” 
5. As the authors point out themselves in 63% of the incomplete examinations the reason for an incomplete 
examination is not stated. Thus in 211 colonoscopies the reason for incompletion is unknown. It would have been interesting to know why the cecum was not reached. 
------------------------------------------------------------------------------- 
Discretionary Revisions (which the author can choose to ignore) 
 Accept after minor essential revisions What next?: 
 An article whose findings are important to those with closely related research interests Level of interest: 
 Acceptable Quality of written English: 
 No, the manuscript does not need to be seen by a statistician. Statistical review: 
Declaration of competing interests: 
I declare that I have no competing interests 
assistant