Measuring childhood mortality through mobile phone interviews in Mozambique

Childhood mortality is a key indicator of progress in health and development in low- and middle-income countries, traditionally measured through household surveys with face-to-face interviews. This study explored an alternative approach that used mobile phone interviews with women in Mozambique.

Using two sampling approaches, we interviewed women of reproductive age about their pregnancy history through mobile phones. The first method used an existing database of phone numbers collected from a national mortality surveillance, Countrywide Mortality Surveillance for Action (COMSA). The second employed random digit dialling (RDD) to generate phone numbers. The COMSA phone sample successfully reached 13,545 women while the RDD sample reached 10,359 women. We compared neonatal (NMR), infant (IMR) and under-five mortality rates (U5MR) to estimates from the United Nations (UN), COMSA and the 2022 Demographic and Health Survey (DHS). The mobile phone-based mortality rates were adjusted using the raking approach.

The mobile phone interviews incorporating pregnancy history yielded recent childhood mortality rates comparable to those reported by the DHS. The 2020-2021 U5MRs were estimated at 59.3 (95% confidence interval [95% CI]: 41.9-76.7) in the COMSA phone sample and 44.9 (95% CI: 9.0-80.7) in the RDD sample, compared to 59.6 (95% CI: 53.7-65.6) in the DHS. These estimates were lower than the UN projections at 71.6 (95% CI: 65.5-87.1) and COMSA at 80.0 (95% CI: 69.0-91.0). We observed similar trends for NMR and IMR. Childhood mortality trends were comparable between the COMSA phone sample and the DHS sample. In contrast, the RDD sample appeared to consistently underestimate childhood mortality compared to the other samples.

Mobile phone surveys, including standard full pregnancy history tools, produced recent childhood mortality levels and trends for national and subnational levels similar to face-to-face approaches such as the DHS.