Table 2 System-related challenges experienced during data collection with mobile phones

(1) Data loss - loss of data may be attributed to users exiting the application before completing the interview. These interviews were not located

Re-training of data collectors so the application is not exited before interview completion.

Re-interview was conducted if the mother/ caregiver agreed

(2) Freezing of phones either due to

a) device problem and/or

b) user related

Device had to be rebooted and/or reset

(3) Partial downloads – user exits or interrupts while the software is being updated or user not checking for updates timeously. This affects the retrieving of a full questionnaire on display.

Bulk SMS reminders were sent to users on a weekly basis to check for updates on the Mobenzi application.

Mobile phone sent to service provider to check if there was a problem with mobile phone. If mobile phone related, it was replaced. If not, software was reloaded.

(4) Missing folders or missing PIDs at scheduled visit timepoints Unable to proceed further while conducting interview.

Data collector had check for updates on mobile phones daily. Missing folders was when the data collector did not check for updates. The data collectors who defaulted where sent SMS reminders individually to check for updates.

Missing PIDs-were reported immediately to the data assistant who investigates and re-assign PIDs to data collectors’ phone.

If still unresolved, mobile device software was reloaded.

(5) Changes in the formatting of dates that seemed to occur when data were merged.

Web developer need to be consistent when setting up date formatting across all platforms e.g. dd/mm/yyyy or yyyy/mm/dd. Different formatting created a problem when merges and data import into statistical packages occurs eg. 12/03/2015 is read as 03/12/2015

The handset used for data collection was a basic Nokia 2330 which was a compact phone with a small display screen and keyboard. The users were retired nurses who had difficulty in viewing information as the screen print was light in colour and small keyboard operation was difficult for them.

Re-training of data collectors and correcting data errors immediately