Rationale for BCT changes between RCT and scale-up
The differences in BCTs coded for the RCT compared to the scaled-up version of INFANT related to modifications made for intervention scalability. For example, the BCT 12.5 (adding objects to the environment) that was coded for the tangible tools given out to participants during the RCT (e.g., balls, fridge magnets, a pedometer for parents). This BCT was not present for the scale-up as these tools were not given out during the scale-up due to funding and logistics of delivering to sites. Notably, there were more unique BCTs present in the scale-up app, primarily due to the app's scope to include more activities and topics (including milk feeding content) which could be coded from explicitly stated written materials.