Reviewer's report 
 Development and psychometric testing of the Visual Analogue Scale for Irritable Bowel Syndrome Title: 
(VAS-IBS) 
 1  20 December 2006 Version: Date: 
 Nicholas J Talley Reviewer: 
Reviewer's report: 
General 
I enjoyed reading this initial validation study of a new measure for irritable bowel syndrome. However, the 
authors need to consider a number of issues, as listed below. 
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Major Compulsory Revisions (that the author must respond to before a decision on publication can be reached) 
1. It is unclear to me what the purpose of this measure is and the authors need to define it better in terms of 
current and future studies. I presume the measure will be primarily used to assess patient status over time. 
It doesn’t appear to be a particularly useful diagnostic measure, as it doesn’t include standardized 
diagnostic criteria for IBS such as the Rome criteria. This seems a limitation and needs to be highlighted in 
the Discussion if any diagnostic utility is envisioned. 
2. A critical issue the authors need to consider and discuss is what is clinically relevant change on this measure? This is not considered in Discussion, but one could argue that changes of a small degree on a 
visual analog scale could be clinically meaningless and, hence, the utility of the measure in practice is 
questionable. Without knowing a clinically minimal relevant change, one could argue the questionnaire has no utility right now. 
3. The diagnosis of IBS here is important. How many of these patients fulfilled Rome or Manning criteria for 
IBS? It may be important to consider this variable in terms of all the analyses. 
4. I do not understand the comment in the Results that states ‘it was simple to form an opinion based on the 
results.’ What do the authors mean by this? What kind of clinical opinion? This seems vague and 
potentially misleading as stated. 
5. Initial validity only was evaluated. There was no test retest reliability assessed, which seems important. In 
fact, the authors should strive to include this in a revised manuscript as it is simple to do and could be highly 
relevant. There are no data on the discriminant validity of the measure, which could be important if this is 
considered to potentially be some kind of diagnostic tool. 
6. The lack of males in the study seems a significant limitation, although presumably acceptable for initial 
validation. 
------------------------------------------------------------------------------- 
Minor Essential Revisions (such as missing labels on figures, or the wrong use of a term, which the author can be trusted to correct) 
------------------------------------------------------------------------------- 
Discretionary Revisions (which the author can choose to ignore) 
 Unable to decide on acceptance or rejection until the authors have responded to the major What next?: 
compulsory revisions 
 An article of importance in its field Level of interest: 
 Acceptable Quality of written English: 
 No, the manuscript does not need to be seen by a statistician. Statistical review: 
Reviewer's report 
 Development and psychometric testing of the Visual Analogue Scale for Irritable Bowel Syndrome Title: 
(VAS-IBS) 
 1  20 December 2006 Version: Date: 
 Nicholas J Talley Reviewer: 
Reviewer's report: 
General 
I enjoyed reading this initial validation study of a new measure for irritable bowel syndrome. However, the 
authors need to consider a number of issues, as listed below. 
------------------------------------------------------------------------------- 
Major Compulsory Revisions (that the author must respond to before a decision on publication can be reached) 
1. It is unclear to me what the purpose of this measure is and the authors need to define it better in terms of 
current and future studies. I presume the measure will be primarily used to assess patient status over time. 
It doesn’t appear to be a particularly useful diagnostic measure, as it doesn’t include standardized 
diagnostic criteria for IBS such as the Rome criteria. This seems a limitation and needs to be highlighted in 
the Discussion if any diagnostic utility is envisioned. 
2. A critical issue the authors need to consider and discuss is what is clinically relevant change on this measure? This is not considered in Discussion, but one could argue that changes of a small degree on a 
visual analog scale could be clinically meaningless and, hence, the utility of the measure in practice is 
questionable. Without knowing a clinically minimal relevant change, one could argue the questionnaire has no utility right now. 
3. The diagnosis of IBS here is important. How many of these patients fulfilled Rome or Manning criteria for 
IBS? It may be important to consider this variable in terms of all the analyses. 
4. I do not understand the comment in the Results that states ‘it was simple to form an opinion based on the 
results.’ What do the authors mean by this? What kind of clinical opinion? This seems vague and 
potentially misleading as stated. 
5. Initial validity only was evaluated. There was no test retest reliability assessed, which seems important. In 
fact, the authors should strive to include this in a revised manuscript as it is simple to do and could be highly 
relevant. There are no data on the discriminant validity of the measure, which could be important if this is 
considered to potentially be some kind of diagnostic tool. 
6. The lack of males in the study seems a significant limitation, although presumably acceptable for initial 
validation. 
------------------------------------------------------------------------------- 
Minor Essential Revisions (such as missing labels on figures, or the wrong use of a term, which the author can be trusted to correct) 
------------------------------------------------------------------------------- 
Discretionary Revisions (which the author can choose to ignore) 
 Unable to decide on acceptance or rejection until the authors have responded to the major What next?: 
compulsory revisions 
 An article of importance in its field Level of interest: 
 Acceptable Quality of written English: 
 No, the manuscript does not need to be seen by a statistician. Statistical review: 
Please review this paper.
user
Reviewer's report 
 Development and psychometric testing of the Visual Analogue Scale for Irritable Bowel Syndrome Title: 
(VAS-IBS) 
 1  20 December 2006 Version: Date: 
 Nicholas J Talley Reviewer: 
Reviewer's report: 
General 
I enjoyed reading this initial validation study of a new measure for irritable bowel syndrome. However, the 
authors need to consider a number of issues, as listed below. 
------------------------------------------------------------------------------- 
Major Compulsory Revisions (that the author must respond to before a decision on publication can be reached) 
1. It is unclear to me what the purpose of this measure is and the authors need to define it better in terms of 
current and future studies. I presume the measure will be primarily used to assess patient status over time. 
It doesn’t appear to be a particularly useful diagnostic measure, as it doesn’t include standardized 
diagnostic criteria for IBS such as the Rome criteria. This seems a limitation and needs to be highlighted in 
the Discussion if any diagnostic utility is envisioned. 
2. A critical issue the authors need to consider and discuss is what is clinically relevant change on this measure? This is not considered in Discussion, but one could argue that changes of a small degree on a 
visual analog scale could be clinically meaningless and, hence, the utility of the measure in practice is 
questionable. Without knowing a clinically minimal relevant change, one could argue the questionnaire has no utility right now. 
3. The diagnosis of IBS here is important. How many of these patients fulfilled Rome or Manning criteria for 
IBS? It may be important to consider this variable in terms of all the analyses. 
4. I do not understand the comment in the Results that states ‘it was simple to form an opinion based on the 
results.’ What do the authors mean by this? What kind of clinical opinion? This seems vague and 
potentially misleading as stated. 
5. Initial validity only was evaluated. There was no test retest reliability assessed, which seems important. In 
fact, the authors should strive to include this in a revised manuscript as it is simple to do and could be highly 
relevant. There are no data on the discriminant validity of the measure, which could be important if this is 
considered to potentially be some kind of diagnostic tool. 
6. The lack of males in the study seems a significant limitation, although presumably acceptable for initial 
validation. 
------------------------------------------------------------------------------- 
Minor Essential Revisions (such as missing labels on figures, or the wrong use of a term, which the author can be trusted to correct) 
------------------------------------------------------------------------------- 
Discretionary Revisions (which the author can choose to ignore) 
 Unable to decide on acceptance or rejection until the authors have responded to the major What next?: 
compulsory revisions 
 An article of importance in its field Level of interest: 
 Acceptable Quality of written English: 
 No, the manuscript does not need to be seen by a statistician. Statistical review: 
assistant