Reviewer ’s report  
 
Title: Cross Design Analysis of Randomized and Observational Data - Application to 
Continuation Rates for a Contraceptive Intra Uterine Device Containing Levonorgestrel in 
Adolescents and Adults  
 
Version: 0 Date: 04 Aug 2018  
 
Reviewer: Omar Mamdouh Mohamed Hussein Shaaban  
 
Reviewer's report:  
 
1. The authors are combining retrospective data from an observational study and a RCTs  
To reach more accurate estimation of the continution rate of LNG -IUS 
2. Title should contain LNG -IUS 
3. How they did choose the studies that are going to be included  
4. They should spill the outcomes clearly at the methodology section  
5. Discussion section is very short does not express why and what is the benefit of doing suc h 
study in -spite that there are other large RCTs that tested the continuation rate of LNG -IUS 
6. They conclude in their analysis that combination of data is beeter from where they had reched 
this conclusion  
 
 
Are the methods appropriate and well described?  
If not, please specify what is required in your comments to the authors.  
 
Unable to assess  
 
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.  
 
No 
 
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 recommend additional statist ical review  
 
Quality of written English  
Please indicate the quality of language in the manuscript:  
 
Not suitable for publication unless extensively edited  
 
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  
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financially from the publication 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 com peting interests in relation to this paper?  
 
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.  
 
None  
 
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