Development of the IDR App
The IDR App was build using the multiple-pass method to collect longitudinal dietary data of infants aged 10th, 12th, 15Testing and piloting of FFQ App and IDR App: The Apps were tested in the field by interviewing ten participants. Testing errors such as App crashing and failure dropdown menu items were identified. The errors were resolved by the nutritionist and developers. It was then piloted by interviewing ten non-study respondents from the study area. Nutrition experts observed the data collection process as the data collectors used the Apps. These observations specific to the usability aspects of the Apps were: (i) the ease of App navigation for data collectors, encompassing actions such as one-tap interactions to access menus or progress to subsequent sections, (ii) the clarity of questions for data collectors, evaluating their ability to read and comprehend the content, (iii) the efficacy of communication between data collectors and participants during the question delivery, (iv) the functionality of App when a data collector captured images of the supplements, (v) the ease for a participant to effortlessly identify a food items displayed by the App, (vi) the ease for data collectors to locate appropriate menu items within the App after concluding the FFQ interview, for the purpose of transitioning to the DHQ interview, (vii) the recognition and responsiveness of data collectors to alerts displayed in the App, particularly concerning data entry errors followed by the ability of data collectors to revisit these questions for the purpose of making corrections were also scrutinised.Training of data collectors: FROs (Field Research Officers) who were qualified ANM (Auxiliary Nurse Midwife) were recruited. They were trained for three days on how to use the Apps. The first two days of training focused on the concept of nutrition, technical details and demonstration of the App. On the last day, they used the App independently to enter dietary data.