Title: Analyzing Factors Affecting Age at First Birth among Married Women in Somalia: A
Bayesian Shared Frailty Modeling Approach using SDHS 2020
Version: 2 Date: 16 Feb 2025
Reviewer's report:
The authors used  farilty models for survival to assess factors influencing age to give first birth
among woemn in Somalia. The statistical analysis part is innovatie and strengthens the analysis.
However, authors need to revise the presentation of their models and results to make their
readable to people without much training in Bayesian statistics. Please see my comments below.
Major comments
1. In the abstract, the author mentioned that Region, Residence, and Husband's desire for children
are statistically significant factors. It is recommended to present the effect magnitude, e.g.,
hazard ratio in additional to this claim.
2. Section 2.1., unless the authors can show its influence on women’s first-birth age, it is
unnecessary to describe Somalia’s geographic information in the method section.
3. Section 2.4: it is recommended to describe variable types. For example, are they continuous
or categorical? If categorical, what’s the category classifications?
4. Statistical analysis: it depends on author’s decision, but they should consider whether it is
necessary to include all the model descriptions in this Section. For example, the authors describe
all the four distributions in the AFT model. These models are well known to readers with
experience in statistics. For readers who do not care much about the technical details, these
components are unnecessary. Thus, I would include them in a supplementary. Same comment
for the introduction to Bayesian analysis.
5. Section 3.1, by looking at the KM plot, the authors claimed that most women in the study
gave birth soon after marrying. Please justify this point. I can only see that at age 20, roughly
50% women gave birth. I do not see the event of marriage in this plot.
6. Section 3.1., please clarify that “Somali women typically have a median survival time of 19
years postmarriage before having their first child, with a 95% confidence interval ranging from
19.0 up to19.1 years.” Does that mean the median time for Somali women to have their children
after marriage is 19 years?
7. Table 2, Figure 2, Figure 3, Figure 4, Figure 5, Figure 6, Figure 7, Figure 8, Figure 9, Figure
10, and Table 6 can be included in a supplementary.
8. Please use hazard ratio names for coefficient instead of beta[number] in Table 3 and 5. They
are unreadable.
9. Please discuss potential limitations for using shared frailty models? What’s the risk of using
reported region to classify women? I don’t think women living in the border of two regions
share the same hospital access (and frailty) with women living in the center of a region. Those
living in the border may go the other region than they are reported to seek health care. Please
give some comments on this situation.
Minor comments
1. Page 2, Introduction: “In the United States, the average age at first birth among mothers aged
40 up to 44 years increased from 23 in 1990 to 26 in 2018”. Please clarify this claim. What is
the average in US, 40 to 44, or 23 to 26?
2. Section 2.3 contains only one sentence and can be added to Section 2.2.
3. Section 2.5 mentions WAIC and LOOIC without giving their full name. Please give the full
term at the first time.
4. Section 2.5.1 and 2.5.2 can be combined.