Reviewer ’s report  
 
Title: Intimate partner violence against women in Nigeria: a multilevel study investigating the 
effect of women's status and community norms.  
 
Version: 0 Date: 07 Apr 2018  
 
Reviewer: Nazeem Muhajarine  
 
Reviewer's report:  
 
While this manuscript reports results that are similar to previous well -conducted studies on 
intimate partner violence (IPV) and their risk factors, what this paper adds are three things: the 
analysis is based on a national survey in Nigeria in 2013 and th erefore is of good scope (and 
generalizability); it reports a carefully constructed two -level analysis --individual/respondent and 
aggregated response at a 'community' level; and it reports on a construction of a multi -
dimensional women's status derived var iable which is the primary exposure variable considered 
in relation to IPV. For these reasons, I am positively disposed to the manuscript and recommend 
that it be considered for publication, but after revisions (for greater clarity and potentially even 
greater contribution to the literature).  
 
The revisions required, perhaps in the order of priority are the following.  
1. The women status derived variable need far greater detail in reporting. This is the key 
exposure variable, and while there is some detail provided of the eight dimensions that 
comprise this derived variable, it leaves out sufficient detail to raise several questions. How 
was the index created --e.g. were all items representing 8 areas/domains included as 
individual and separate items in the P C analysis or were a mix of single items and some 
domain -related summary scores included (participation in household decision making will be 
an example of the latter)? It is suggested that more detail of the construction of this key 
variable provided (the results of the PC analysis with item -loadings, for example). Also, the 
tables show that this variable was grouped into low, middle and high --are these tertiles? Need 
to state how this variable was included in the model building.  
The rationale for includin g these eight dimensions to create a summative variable on women 
status would be helpful; later in the discussion how this particular variable compares with similar 
measures of 'women status/empowerment' from previous studies would nicely close the loop on  
the discussion and relevance of this particular operationalizing of this important variable.  
 
2. Report the percent variance explained by variables in each level --individual, 'community' 
level, and both individual and community level, as this is a key co ntribution of this paper. 
While I recognize that when the variance are decomposed the percent variance explained 
appear not much, it is important to reveal to the readers very clearly, and explicitly, the 
variance composition due to each level of variables  used in the models. (This could be done 
in a pie -chart, if the authors wish.)  
 
3. I appreciate seeing figure 3, as the results shown here of the cross -level interactions is the 
key finding of this paper. However, rather than reporting (marginal) probabili ties, I would 
suggest reporting adjusted odds ratios and their 95% CIs in this figure. The ORs would 
clearly show the reversing of direction of associations between women status and IPV when 
community context (justifies/do not justify violence against wome n) are considered. I would 
also suggest including/listing all of the covariables that the model had adjusted for in the 
final cross -level interaction model.  
 
4. I agree with the authors that the contextual variable, especially the reported attitudes toward s 
wife-beating, is not a 'pure' context or area level variable, but rather a variable aggregated to 
the community/area level based on individual respondents surveyed. This point was touched 
on by the authors as a point to consider in the limitation section , but perhaps a little more 
elaboration is justified. Also, could the authors comment on what basis (rationale) the five 
scenarios that were included in this variable --attitudes towards wife beating --selected. 
Similarly, on what basis were the items select ed for inclusion of a measure of partner 
controlling behavior.  
 
5. Since contextual variables were created from aggregated individual responses for each 
PSU/community, and the respondents for each PSU were a female, or a male respondent, 
what is the stabi lity of these contextual variables (based on sample size of female/male 
respondents at PSU level)? Were all PSUs included in this analysis compared to that 
available when data were collected. What selection effects might have been an issue here?  
 
6. Since this analysis is based on cross -sectional data, need to acknowledge explicitly that it is 
difficult to tease out the time -order of attitude (of wife beating) from IPV experience.   
 
7. Did the authors test for additional cross -level interactions, e.g. cont ext changing effects of 
age on IPV, etc? If so, please state; if not, please clarify that only one cross -level interaction 
was tested (based on a theoretical proposition).  
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:  
 
Needs some language corrections before being published  
 
Declaration of competing interests  
Please complete a declaration of competing interests, considering the following questions:  
 
1. Have you in t he 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 organisat ion that may in any way gain or lose  
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 reimbursemen ts, 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 t his 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.  
 
No competing interest.  
 
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