Variation in the operationalisation of dose in implementation of health promotion interventions: insights and recommendations from a scoping review.

Dose is not a well-defined or consistently applied concept in evaluations of health promotion interventions. While current approaches to conceptualisation and measurement of dose are suitable for interventions in organisational settings, they are less well suited to policies delivered at a population level. Dose often accompanies a traditional monotonic linear view of causality (e.g. dose response) which may or may not fully represent the intervention's theory of how change is brought about. Finally, we found dose and dosage to be used interchangeably. We recommend a distinction between these terms, with 'dosage' having the advantage of capturing change to amount 'dispensed' over time (in response to effects achieved). Dosage therefore acknowledges the inevitable dynamic and complexity of implementation.