Review for 10.1186/1471-230X-7-16 (2007)

Reviewer's report 
 Development and psychometric testing of the Visual Analogue Scale for Irritable Bowel Syndrome Title: 
(VAS-IBS) 
 1  21 December 2006 Version: Date: 
 Margaret Reilly Reviewer: 
Reviewer's report: 
General 
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Major Compulsory Revisions (that the author must respond to before a decision on publication can be 
reached) 
Introduction 1. The authors should address the numerous publications that discuss QOL questionnaires for IBS (A medline search yields 86 references as of Dec 15, 2006). I have a similar concern about the literature on 
symptom questionnaires. 
2. The pros and cons of using one-item scales to measure complex concepts (e.g., social, psychological, 
work productivity aspects of QOL) should be addressed. 
3. The authors do not address the vast literature that has disaggregated symptoms from QOL, but instead 
have combined the two concepts in a single measure without any consideration of the disadvantages of 
doing so. 
4. The authors arbitrarily choose 10 or fewer items as the number for a questionnaire but offer no rationale for this choice and eliminate from discussion much of the work in this arena on that basis. A new 
questionnaire may very well be needed, but the authors have not made the case for it. 
5. The choice of a recall interval of one week (page 4) for a new questionnaire should be based on more 
than the fact that other scales use this interval. The choice should be based on the intended use, the nature 
of the condition, recall burden, etc. 
6. On page 4, it is stated that “this scale has earlier been used to measure well-being and symptoms in 
patients with IBS” and references are given. This belongs in the review of the literature. I think the authors mean to say that this method of VAS, not the specific items, have been used previously, but it is not clear. 
7. Page 5: information on the patient sample selection is contradictory. The authors state that they wanted to 
recruit patients with long and short duration of symptoms and from gastroenterology clinics as well as 
primary care clinics, but all subjects were recruited in a university gastroenterology clinic. No information is provided about disease duration. 
8. Page 6: the response rate from this highly selected patient population is low (less than 40%), but this is 
not explicitly stated. The authors fail to discuss adequately the limitations of the research due to the sample 
bias, i.e., that it is based on a low response rate of women attending a university specialty clinic in Sweden. 
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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. Grammatical error page 5: should be “doctors and nurses who…” 2. Agreement of the definition is not defined and it is not clear what that means. 3. Page 7: I do not know how to interpret the sentence: “The content validity index was judged…”. It is not 
clear how this sentence relates to the previous citation of the index on page 5. 
4. No information is provided on the scoring of the VAS, i.e., how the patient’s marks on the lines are handled. VAS can be cumbersome to score since the distance from the anchor to the mark must be measured, often by a hand-held ruler. The authors say it took one minute, but don’t say how it was done. 
5. p.10-gramatical error: further items should be additional items. 
6. p-12. “ ..based on 16 questions..” What are the 16 questions? I count 7 items in the final questionnaire, e.g., as in Table 5. It would help to see the final questionnaire proposed. 7. Page 15: Quick should be quickly. Patients should be patients’. 
8. The authors’ hopes are not appropriate in a conclusion. 
9. Table 2: need definitions of the scoring in the footnotes. 
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Discretionary Revisions (which the author can choose to ignore) 
1. Abnormal stool passage can be subsumed into the two types of bowel patterns (diarrhea and 
constipation). The discussion of it on page 2 just confuses the issue. 
2. The authors dismiss the suggestion of including “food intolerance’ as not part of IBS, but others would 
argue that it has important implications for QOL. 
 Unable to decide on acceptance or rejection until the authors have responded to the major What next?: 
compulsory revisions 
 An article whose findings are important to those with closely related research interests Level of interest: 
 Needs some language corrections before being published Quality of written English: 
 No, the manuscript does not need to be seen by a statistician. Statistical review: 
Declaration of competing interests: 
I decalre that I have no competing interests.