Table 2 Summary of activities to develop the Initial Programme Theory of the KP-CBART model

Theory gleaning phase

(Data collection)

Step 1: Review of the intervention logic model and professional experience of the researcher

•To elicit the starter programme theory (the pre-existing theory of KP-CBART informed by the intervention logic model)

•To explain how different programme activities will contribute to a series of results that produce the intended outputs and outcomes

Step 2: Literature review of policy and programme documents on the implementation policy, guidelines, framework and journal articles on community-based HIV prevention, care and treatment for key populations

•To describe the history and evolution of KP-CBART model implementation in in SSA including Nigeria and the policy environment

•To describe the programme strategies and activities and to identify contextual factors

Step 3: Scoping review on outcomes along the cascade of HIV care and treatment continuum

•To identify the outcomes of the CBART intervention for KP

Step 4: In-depth interviews with programme managers

•To elicit the starter programme theory programme managers’ assumptions (folk theories)

•To map out programme- specific CMO configurations

•To refine the starter programme theory

Step 5: Review of an existing programme theory for antiretroviral treatment adherence club programme in South Africa to inform the CMOc and programme theory for KP-CBART

To adapt the existing programme theory of the ART adherence club intervention to suit the KP-CBART programme Nigeria, including the mechanisms

Eliciting the initial programme theory

(Data analysis)

Step 6: Synthesis of results

Triangulation of data and analysis of Context-Mechanism-Outcome configurations for KP-CBART programme and the IPT