Title: Rural-urban migration as a factor associated with physical and sexual intimate partner
violence Peru 2015-2017: a secondary analysis of a national study.
Version: 2 Date: 29 Dec 2021
Reviewer:  Tina L. Bloom
Reviewer's report:
I enjoyed reading this manuscript and found it generally well-written. I think it could make an
important contribution to the literature.
Here is my understanding of the methods: The purpose of this interesting study was to identify
the association between internal migration and physical and/or sexual violence against women
of childbearing age in the last 12 months, among a population-based sample of Peruvian
women. Specifically, the sample used were women age 15-17 surveyed 2015-2017 in Peru’s
Demographic and Family Health Survey (DHS) who were randomly selected to complete
the violence module. This module included questions about physical and sexual violence and
about where women lived for the longest until they were 12 years old (referred to as “primary
residence”), their current place of residence at the time of the survey, and the amount of time
they lived at the current place of residence. The exposure variable was internal migration,
operationalized from those three questions: 1) current place of residence, 2) primary residence
before 12 years of age and 3) number of years of residence in the current place.
From these data, the authors classified the participants either as nonmigrants (defined as those
who reported having lived in the same place all their lives, i.e., primary residence before age
12 and current residence are the same) or as migrants. (I found this definition of nonmigrants
was easy to understand and made sense.) The operational definition of migrants is described as
those who reported having lived for 5 years or more in the current location. The authors further
stratify the sample of migrants by classifying them as having lived in the place to which they
migrated for 5-12 years, 13-20 years, or more than 21 years, as well as whether they were (based
on the difference between their primary residence and current residence) rural-rural migrants,
urban-urban migrants, urban-rural migrants, or rural-urban migrants.
The operational definition of “migrants” as “those who reported having lived for 5 years or
more in the current location” is where I got stuck in my understanding of their methods. I
read and re-read the methods and tables over and over again but still found it unclear. I have a
guess that other readers may have the same issue, and I think some clarification here would be
beneficial. Presumably migrants were first and foremost classified as migrants if they (unlike
those classified as nonmigrants) reported that their primary residence and current residence were
not the same. It might be helpful to actually say this. The part about “having lived for 5 years or
more in the current location” the operational definition is where I got more tangled up, and I was
not clear why this was the criteria. It also seems that those who migrated more recently – let us
say for example, a rural woman who recently followed a partner to the city, in the past five years
or less – were therefore excluded from these data, and I’m not clear why that decision was made.
(It also seems a limitation for the findings.) When looking at a recent outcome (past-year IPV
exposure), it seems confusing to exclude the women who have the most recent experience with
the exposure variable and who would seem to be at the highest risk. It also would be useful to
know how the authors operationalized definitions of rurality and urbanity. I think others might be
a little hard-pressed to interpret findings or replicate their methods because of these limitations,
but these issues seem like they could be addressed in revision.
In a more minor point of feedback, there are a few places I think the manuscript could be
tightened up to be stronger. Specifically, the literature review as written seems heavily focused
on  the contributions of gender roles and cultural and behavioral norms influencing partner
relationships and IPV risk in internal migration. This part of the literature review (while I agree
with it) doesn't seem to fit the variables looked at in this study very well -- aside from some
measure of women's childhood exposure to IPV  (history of father's physical aggression towards
their mother) it doesn't seem that gender roles or norms are addressed in these data.  The literature
review would be stronger if it addressed the extant literature on internal migration and IPV more
directly, including what is known/unknown in the Peruvian context (has other research specific
to the impact of internal migration on IPV been done in Peru? seems like the answer is no?) and
made a strong case for the gap this study addresses.
Conversely, I think the discussion was well done and interesting, and placed the findings in the
extant literature nicely.  I think it could be strengthened further with some explicit discussion of
the authors' recommendations for future research, practice, and/or policy based on their findings.
Thank you for the opportunity to read this interesting study; I hope my comments were useful.