Evaluating complex interventions in context: systematic, meta-narrative review of case study approaches

Abstract

Background There is a growing need for methods that acknowledge and successfully capture the dynamic interaction between context and implementation of complex interventions. Case study research has the potential to provide such understanding, enabling in-depth investigation of the particularities of phenomena. However, there is limited guidance on how and when to best use different case study research approaches when evaluating complex interventions. This study aimed to review and synthesise the literature on case study research across relevant disciplines, and determine relevance to the study of contextual influences on complex interventions in health systems and public health research. Methods Systematic meta-narrative review of the literature comprising (i) a scoping review of seminal texts (n = 60) on case study methodology and on context, complexity and interventions, (ii) detailed review of empirical literature on case study, context and complex interventions (n = 71), and (iii) identifying and reviewing ‘hybrid papers’ (n = 8) focused on the merits and challenges of case study in the evaluation of complex interventions. Results We identified four broad (and to some extent overlapping) research traditions, all using case study in a slightly different way and with different goals: 1) developing and testing complex interventions in healthcare; 2) analysing change in organisations; 3) undertaking realist evaluations; 4) studying complex change naturalistically. Each tradition conceptualised context differently—respectively as the backdrop to, or factors impacting on, the intervention; sets of interacting conditions and relationships; circumstances triggering intervention mechanisms; and socially structured practices. Overall, these traditions drew on a small number of case study methodologists and disciplines. Few studies problematised the nature and boundaries of ‘the case’ and ‘context’ or considered the implications of such conceptualisations for methods and knowledge production. Conclusions Case study research on complex interventions in healthcare draws on a number of different research traditions, each with different epistemological and methodological preferences. The approach used and consequences for knowledge produced often remains implicit. This has implications for how researchers, practitioners and decision makers understand, implement and evaluate complex interventions in different settings. Deeper engagement with case study research as a methodology is strongly recommended.

Revisiting concepts of evidence in implementation science

“…In some cases, the context for delivery (e.g., a particular clinical setting) is relatively stable, but the target of the intervention (e.g., a particular pathophysiology; guidelines for cancer screening) is dynamic and emergent. In a more complex intervention trial, both context and targets are dynamic and emergent [ 22 , 84 ].…”

Adapt or die: how the pandemic made the shift from EBM to EBM+ more urgent

“…41 One approach to researching these generative mechanisms is the in-depth case study, a mixed-method design in which data collection, interpretation and synthesis are oriented to producing a rich description of a phenomenon in context. 42 Hypotheses are explored and tested by constructing a plausible story (narrative synthesis) in which all data-qualitative and quantitative-are accounted for. Local public health interventions, even when part of national policy, are typically path-dependent (shaped and constrained by what has happened here previously) and emergent (they grow organically over time); they tend to be implemented and improved through testing and iteration in the real world.…”

Understanding dynamic complexity in context—Enriching contextual analysis in implementation science from a constructivist perspective

“…However, as not all participants are equally available for the interviews or express themselves openly, interviews only provide initial qualitative information, e.g., about participants' levels of agency, their relationships, mental models and expectations (69). Therefore, using a range of qualitative methods including various forms of interviews, direct observation, document analysis, or case study approaches is recommended (24,69,97).…”

“…Case studies are defined as "qualitative approach[es] in which the investigator explores real-life, contemporary system (a case) or multiple bounded systems (cases) over time, through detailed, in-depth data collection" [27, p.153]. Case study approaches cannot only be applied to study context before the start of an implementation science project (e.g., to inform for intervention development), but also to evaluate complex interventions (97).…”