Accounting for complexity - Intervention design in the context of studying social accountability for reproductive health.

: Social accountability interventions aim to propel change by raising community voices and holding duty bearers accountable for delivering on rights and entitlements. Evidence on the role of such interventions for improving community health outcomes is steadily emerging, including for sexual and reproductive health and rights (SRHR). However, these interventions are complex social processes with numerous actors, multiple components, and a highly influential local context. Unsurprisingly, determining the mechanisms of change and what outcomes may be transferable to other similar settings can be a challenge. We report our methodological considerations to account for complexity in a social accountability intervention exploring contraceptive uptake and use in Ghana and Tanzania. : The Community and Provider driven Social Accountability Intervention (CaPSAI) study explores the relationship between a health facility-focused social accountability intervention and contraceptive service provision in two countries. This 24-month mixed-method quasi-experimental study, using an interrupted time series with a parallel control group, is being undertaken in 16 sites across Ghana and Tanzania in collaboration with local research and implementation partners. The primary outcomes include changes in contraceptive uptake and use. We also measure outcomes related to current social accountability theories of change and undertake a process evaluation. We present three design components: aspects of co-design, 'conceptual' fidelity, and how we aim to track the intervention as 'intended vs. implemented' to explore how the intervention could be responsive to the embedded routines, local contextual realities, and the processual nature of the social accountability intervention. : Through a discussion of these design components and their rationale, we conclude by suggesting approaches to intervention design that may go some way in responding to recent challenges in accounting for social accountability interventions, bearing relevance for evaluating health system interventions.