Reviewer ’s report  
 
Title: Short Birth Interval and Associated Factors among Women of Chil d Bearing Age in 
Northern Ethiopia, 2016  
 
Version: 0 Date: 12 Oct 2018  
 
Reviewer: Raymond Tutu  
 
Reviewer's report:  
 
The authors sought to understand factors associated with birth interval. While this attempt will 
add to knowledge on the topic, I recommend the following edits and revisions.  
1. The manuscript requires an extensive c opy-editing. Below are few copy -editing mistakes:  
Line 77 page 3: SB not defined previously. Do so or stick with SBI. Recast sentence.  
Line 80 to 83 page 4: break into two sentences.  
Line 84 page 4: a word is missing.  
Line 95 page 4: you mean "existing"?  
 
2. Study population:  
For the excluded population (line 117 -118 on page 5), the women with history of abortion 
variable ought to be explained. Clarify if that included spontaneous abortions and/or induced 
abortions and provide justification.  
 
3. Sample size  determination and sampling procedure:  
(i) Line 123 page 5: provide a scientific justification for the assumption of 48%, given that the 
cited study was in Tanzania. (ii) Line 130 page 6: PPS is conventionally known as Probability 
proportional to size. Ple ase recast.  
 
4. Data collection tools: while the authors mention drawing on existing questionnaires 
("published literature"), no mention is made about the exact variables (questions) they are 
interested in and the conceptual justification. If the questionn aire had different modules, what 
were they and why? Specifically, while the outcome variable is absolutely clear, the predictor 
variables (whether proximate or non -proximate) are not explicitly indicated and the theoretical 
reasoning almost entirely missin g. 
 
5. Results  
(i) Short birth interval: while I do not disagree with the authors on the operational definition of 
short birth interval, primarily because of WHO recommendations, birth intervals of less than 24 
month are associated with much negative outco mes; this has been indicated in their introduction. 
Therefore, given the high fertility rate, it may be prudent to execute two sets of analyses: one 
with SBI <24 months and the other as done in the manuscript.  
(ii) Lines 250 -251 page 12: recast. I think "w ere" is not needed.  
(iii) Line 259 -20 page 12: the high proportion of women who got pregnant while their menses 
had not resumed (out of the 17% who got pregnant and yet wanted to limit) is an important 
reason to analyze post -partum amenorrhea and post -partum infecundability, as well as how that 
is associated with birth intervals although duration of breastfeeding has been analyzed. Both of 
these variables are prominent in the conceptual and praxis literature. I strongly encourage authors 
to add these analys es if data was collected on these variables.  
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.  
 
Yes 
 
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 am able to assess the statistics  
 
  
Quality of written English  
Please indicate the quality of language in the manuscript:  
 
Not suitable for publication unless extensively edited  
 
Declaration of competing interests  
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