Review for 10.1186/s12876-017-0684-8 (2017)

Reviewer ’s report  
 
Title:  Design and Validation of a German Version of the GSRS -IBS - an Analysis of 
Psychometric Quality and Factorial Structure  
 
Version: 0 Date: 24 Aug 2016 
 
Reviewer:  Raika  Jamali  
 
Reviewer’s report:  
 
Dear Associate Editor,  
 
Thank you for sending me the article entitled "Validation of a German Version of the GSRS -IBS 
- An analysis of psyc hometric quality and factorial structure" for review. This cross sectional 
study evaluated the validity of German Version of the GSRS -IBS in a sample of German IBS 
patients. There are some comments about the article as the followings:  
 
1-Please describe th e method of sample selection in the method part of abstract. Were they 
randomly selected?  
 
2- In the conclusion of abstract (The German version of the GSRS -IBS proves to be an effective, 
reliable, and valid questionnaire for the assessment of IBS). Which a spect of IBS is of concern? 
Please clarify that "symptom severity of IBS" is noted in this study.  
 
3-Please select the key words based on MeSH terms.  
 
4-The background is very long. Please summarize the importance of performing the study in 
Germany. I recomm end the authors to remove the descriptions of GSRS -IBS in the background 
(The final version of the GSRS -IBS includes 13 items. The contents of these items are meant to 
exclusively capture IBS constructs. Furthermore, neither ceiling effects nor redundant 
information should be evident with the chosen items. A factor -analytic examination of the 13 
items in a validation cohort provided the following five factors: pain, diarrhoea, satiety, 
constipation, and bloating. All scales comprising of two to four items p resented with satisfactory 
internal consistencies between .74 and .85 using Cronbach's Alpha.) to the method part.  
 
5-Please do not use abbreviations in tables and figure. I recommend using the full word in foot 
notes of tables.  
 
6-Selecting the students as  the control group is a limitation of study. I recommend addressing 
this issue in the discussion.  
 
7- I recommend the authors to change the title. The study consists of designing and validating the 
questionnaire in a sample of IBS patients.  
 
Are the methods appropriate and well described?  
If not, please specify what is required in your comments to the authors.  
 
Yes 
 
Does the work include the necessary controls?  
If not, please specify which controls are  required in your comments to the authors.  
 
No 
 
Are the conclusions drawn adequately supported by the data shown?  
If not, please explain in your comments to the authors.  
 
Yes 
 
Are you able to assess any statistics in the manuscript or would you recommend an 
additional statistical review?  
If an additional statistical review is recommended, please specify what aspects require further 
assessment in your comments to the editors.  
 
I reco mmend additional statistical review  
 
Quality of written English  
Please indicate the qu ality of language in the manuscript:  
 
Acceptable  
 
Declaration of competing interests  
Please complete a declaration of competing interests, considering the following questions:  
 
1. Have you in the past five years received reimbursements, fees, funding, or salary from an 
organisation that may in any way gain or lose financially from the publication of this 
manuscript, either now or in the future?  
 
2. Do you hold any stocks or shares in an organisation that may in any way gain or lose 
financially from the public ation of this manuscript, either now or in the future?  
 
3. Do you hold or are you currently applying for any patents relating to the content of the 
manuscript?  
 
4. Have you received reimbursements, fees, funding, or salary from an organization that 
holds or has applied for patents relating to the content of the manuscript?  
 
5. Do you have any other financial competing interests?  
 
6. Do you have any non -financial competing interests in relation to this paper?  
 
If you can answer no to all of the above, write 'I declare t hat I have no competing interests' 
below. If your reply is yes to any, please give details below.  
 
I declare that I have no competing interests  
 
I agree to the open peer review policy of the journal. I understand that my name will be included 
on my report to the authors and, if the manuscript is accepted for publication, my named report 
including any attachments I upload will be posted on the website along with the authors' 
responses. I agree for my report to be made available under an Open Access Creative Commons 
CC-BY license ( http://creativecommons.org/licenses/by/4.0/ ). I understand that any comments 
which I do not wish to be included in my named report can be included as confidential comments 
to the editors, which will not be published.  
 
I agree to the open peer review policy of the journal