Many quality improvement (QI) interventions can be complex, comprising multiple inter-related components that target a range of factors which may lead to change. Some of these components can be focused on the nature of the improvement planned, the place where the change is to occur, the people who are involved and/or the structures and processes within the organisation itself.1 Understanding how the multiple components of such interventions work together to drive an improvement or in those instances where they fail to do so can be challenging. Without adequate assessment of the underlying processes and mechanisms through which change occurs, crucial learning on how best to deliver improvements may be lost to the wider system.