Process evaluations for the scale-up of complex interventions – A scoping review
Authors: Heine Martin , Rathod Lekha , Boateng Daniel , Martens Monika , Van Olmen Josefien , Ku Grace Marie , Klipstein-Grobusch Kerstin 
Published: January 2024

Background: Process evaluation (PE) is an essential part of testing and adapting complex health interventions (CHIs) and involves evaluating what is implemented (and how), mechanisms of change, and how context affects implementation and health outcomes. To address complex health needs, the focus is on developing new CHIs, rather than on adapting and scaling up existing interventions to promote stronger integration, increased population coverage, or comprehensiveness. Therefore, more attention is needed to process evaluations conducted during the scale-up process as they may have distinctive features, stakeholders, or objectives. We aim to describe the current practice of process evaluations conducted during the scale-up of CHIs.
Who is it for? The results of this review are relevant to all stakeholders involved in the scale-up of CHI.
Who did you involve and engage with? All authors of this review have been involved in the scale-up of integrated care across multiple contexts.
What did you do? Eight primary data sources (PubMed, Embase, CENTRAL, Web of Science, CINAHL, Global Health, Scielo and African Index Medicus) and grey literature were searched. Studies were screened following gold standard review procedures. Study demographics, scale-up dimensions (i.e., integration, coverage, comprehensiveness), features of the complex intervention and PE were charted. Process evaluation was further assessed in terms of stakeholders involved and proposed objectives of the PE. For this review, the United Kingdom Medical Research Council’s (MRC) definition of PE was adjusted in terms of “scale-up” instead of “delivery and functioning.”
What results did you get? We identified 10303 unique records of which 34 were included after abstract (n=223) and full-text (n=91) screening. Twenty of the 34 studies were conducted in one or more low-middle income countries (LMICs). Most CHIs studied looked at scale-up of interventions for patient empowerment through digital health, strengthening primary care, or person-centered care models. In the absence of a guiding framework for PEs in the context of scale-up, a variety of other frameworks were often used including the RE-AIM framework (n=5), Consolidated Framework for Implementation Research (n=3), or MRC framework for the PE of CHIs (n=1). Some of these frameworks were subsequently adapted to facilitate unexpected pathways to impact or interactions with contextual factors to emerge as well. Interestingly, in 12 out of 34 studies, beneficiaries (e.g., patients) were not stakeholders in the PE.
What is the learning for the international audience? Process evaluations specific to the process of scaling up is advertently different from implementing a CHI. In the absence of a gold standard framework to guide PE during scale-up, the development of such guidance could be considered.
What are the next steps? We plan to seek further engagement, including with those funded under the “Global Alliance of Chronic Disease” scale-up program, to determine the value and content of a process evaluation framework for scale-up.