Review for 10.1186/s12876-016-0453-0 (2016)

Reviewer’s report  
Title: Evidence of surgical outcomes fluctuates over time: results from a cumulative meta -
analysis  of laparoscopic versus open appendec tomy for acute appendicitis  
 
Version: 1 Date: 27 Jan 2016  
 
Reviewer: Dimitrios Mavridis  
Reviewer’s report:  
I would like to thank the authors for addressing all the comments raised. The manuscript has 
been improved considerably  
 
I have some minor  comments  
 
My only essential comment is that the word 'established evidence' still appears on page 13 line 
28 in a way suggesting that 'established' evidence may change. This is not true, if evidence has 
been established (or better conclusive) using formal  statistical methods, it will most probably not 
change (or it has a 5% type I error as all confidence intervals/methods). There has been a lot of 
effort from scientists stressing the need for conclusive evidence and for not wasting resources in 
the presenc e of conclusive evidence. I believe you should stay on that line.  I would suggest 
changing the word 'established' with 'large intervention effects' and emphasizing that large 
intervention effects are not necessarily conclusive/established and may fluctuat e over time.   
 
other minor comments  
 
The funnel plot explores for small -study effects and not for publication bias. Wording should be 
changed on page 10 line 31  
 
regarding the funnel plots, it is hard to judge asymmetry visually but I get the impression t here is 
none in Figure 3  
 
page 16, line 28, Fourth instead of Forth  
 
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 spe cify which controls are required in your comments to the authors.  
 
Unable to assess  
 
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 o r 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 am able to assess the statistics  
 
Quality of written Engl ish 
Please indicate the quality of language in the manuscript:  
 
Needs some language corrections before being published  
 
Declaration of competing interests  
Please complete a declaration of competing interests, consideri ng 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, e ither now or in the future?  
 
2. Do you hold any stocks or shares in an organis ation that may in any way gain or lose 
financially from the publication of this manuscript, e ither 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 fin ancial competing interests?  
 
6. Do you have any non -financial competing interests  in relation to this pa per? 
 
If you can answer no to all of the above, write 'I declare that 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  
 
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