Table 1 Definition of the process evaluation outcome measures [24-26, 31]

Context

How external factors influence the delivery and functioning of an intervention.

Recruitment and retention

The factors associated with uptake and ongoing engagement with the intervention.

Reach

The extent to which the target audience comes into contact with the intervention.

Implementation

The structures, resources and processes through which delivery is achieved, and the quantity and quality of what is delivered.

Fidelity

The extent to which the intervention is delivered as conceived.