Case study research for better evaluations of complex interventions: rationale and challenges

Abstract

Background The need for better methods for evaluation in health research has been widely recognised. The ‘complexity turn’ has drawn attention to the limitations of relying on causal inference from randomised controlled trials alone for understanding whether, and under which conditions, interventions in complex systems improve health services or the public health, and what mechanisms might link interventions and outcomes. We argue that case study research—currently denigrated as poor evidence—is an under-utilised resource for not only providing evidence about context and transferability, but also for helping strengthen causal inferences when pathways between intervention and effects are likely to be non-linear. Main body Case study research, as an overall approach, is based on in-depth explorations of complex phenomena in their natural, or real-life, settings. Empirical case studies typically enable dynamic understanding of complex challenges and provide evidence about causal mechanisms and the necessary and sufficient conditions (contexts) for intervention implementation and effects. This is essential evidence not just for researchers concerned about internal and external validity, but also research users in policy and practice who need to know what the likely effects of complex programmes or interventions will be in their settings. The health sciences have much to learn from scholarship on case study methodology in the social sciences. However, there are multiple challenges in fully exploiting the potential learning from case study research. First are misconceptions that case study research can only provide exploratory or descriptive evidence. Second, there is little consensus about what a case study is, and considerable diversity in how empirical case studies are conducted and reported. Finally, as case study researchers typically (and appropriately) focus on thick description (that captures contextual detail), it can be challenging to identify the key messages related to intervention evaluation from case study reports. Conclusion Whilst the diversity of published case studies in health services and public health research is rich and productive, we recommend further clarity and specific methodological guidance for those reporting case study research for evaluation audiences.

We Need to Talk About Complexity in Health Research: Findings From a Focused Ethnography

“…There are no easy answers, but as one illustrative example, Lanham et al (2013) employ case studies to highlight the importance of harnessing relationships and self-organization, remaining alert to local needs for modifications, and supporting sense-making, in the scale-up and spread of health care interventions. As another example, more recently, the MRC has commissioned our team to develop guidance on the use of case study methods to appreciate the role of context in shaping complex interventions (Paparini et al, in press).…”

Effectiveness of a Psychosocial Care Quality Improvement Strategy to Address Quality of Life in Patients With Cancer

“…First, randomized clinical trials may not be the best way to answer questions about the effects of interventions in complex systems, because the strict rules entailed by the design do not enable adjustment to the needs of different centers. 47 Second, although a stepped-wedge cluster design provided greater trial efficiency, the 2-year period imposed by economic constraints did not allow us to observe all 3 clusters for at least 1 year or ascertain whether the strategy's effect on patients persisted 1 year after diagnosis. Furthermore, the 4-month implementation period in each cluster, chosen to reduce center waiting times, may have been too…”

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

“…There is growing interest in methodological approaches that support meaningful evaluation of complex interventions in health care [ 1 – 3 ], offer to address issues of causality in complex systems [ 4 , 5 ] and grapple with the thorny issue of what counts as ‘context’ and what as ‘intervention’. Case study research focuses on in-depth explorations of complex phenomena in their natural, or real-life, settings [ 6 ], enabling dynamic understanding of complexity, and surfacing the different logics underpinning causal inferences. While there is wide variation in case study research and its implementation, this approach can provide vital evidence for those concerned with internal and external validity and the likely effects of complex interventions across different settings.…”

“…To address a recognised lack of clarity on how researchers should conduct and report empirical case studies [ 7 ], and especially to address the knotty problem of how context should be understood and operationalised in such studies [ 6 ], we undertook a systematic meta-narrative literature review. This was part of the Triple C (Case study, Context and Complex interventions) study that aims to develop guidance and standards for reporting case study research into the influence of context in complex health interventions.…”