The population is dominated by the local Dholuo speaking people.
One of the Dholuo words used to describe irritability included "ger" which could also mean hostility or provocative.
Where the person being interviewed could not understand English or Swahili, the local dholuo language was used with the assistance of an interpreter.
Following informed consent, a structured questionnaire was administered in the local language (Dholuo or Kiswahili) to obtain information on sociodemographic, health, and obstetric factors.
After obtaining caretaker's written consent, community interviewers administered to the caretakers of all selected children a pre-tested questionnaire written in English and translated into the local dialect (Dholuo).
Interview schedules, information sheets and consent forms were translated from English into local languages (Kiswahili, Dholuo, Runyakitara and Luganda in Uganda; Kiswahili and Dholuo in Kenya) independently by two local researchers.
A screening consent form was administered to eligible participants by trained female nurse-counselors fluent in the local language (Dholuo).
The questionnaires were written in English and then translated into the other commonly spoken languages in Kisumu: Kiswahili and Dholuo.
The FGD guide consisted of 12 open-ended questions with probes about MC uptake and acceptability (Text S1) that were originally drafted in English, then translated into Kiswahili and Dholuo, and then verified by the research team.
Using differential item function analyses, we demonstrated that the scale performed consistently at all three time points, and whether interviews were conducted in English or not (Dholuo or Kiswahili).
The questionnaires and consent documents were developed in English and translated into Dholuo and Kiswahili (the predominant local languages) independently by two indigenous speakers, and discrepancies were resolved with assistance from a third individual.
