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Research Methods & Reporting

Process evaluation of complex interventions: Medical Research Council guidance

BMJ 2015; 350 doi: (Published 19 March 2015) Cite this as: BMJ 2015;350:h1258

From process evaluation to knowledge transfer

The new MRC guidance on process evaluation of complex interventions 1 usefully completes the previous guidance 2,3. Process evaluation, as defined by the MRC guidance, aims to understand the functioning of an intervention, by examining implementation, mechanisms of impact, and contextual factors. According to this definition, this type of evaluation allows a complementary analysis of the efficacy of interventions in order to understand how and why an intervention is effective. This approach is particularly relevant in the context of evaluation of complex interventions, in which the result depends on the interaction between the intervention and its context

In addition to its methodological applications, this guidance allows an approach designed to address the dual challenges currently faced by researchers in the field of complex interventions: the challenge of broadening the scope of interventional research questions and that of knowledge transfer.

Firstly, whether in the field of health services research, evaluation of health policies or health promotion interventional research, the models and tools developed in this guidance extend beyond the conventional experimental paradigms essentially focused on efficacy. These models are consistent with current public health research trends concerning the applicability and transferability 4 of interventions and allow the creation of a conceptual and operational framework promoting the development of other evaluative research questions: what are the conditions of efficacy of an intervention? What conditions promote implementation of an intervention in various contexts? How to achieve a balance between adaptation of interventions and integrity of those components ?

Secondly, because it allows investigation of the mechanisms involved in complex interventions and analysis of the impact of contextual factors on the effects of these interventions, this evaluation can facilitate knowledge transfer (KT) at three levels:

• In the knowledge production process: because definition of the mechanisms and characterization of contexts require mobilization of practicioners’ knowledge in addition to researchers’ knowledge, this type of evaluation encourages closer collaboration, thereby supporting the development of collaborative research 5.
• In the understanding of decision-making processes: if knowledge and intervention diffusion strategies are considered to be complex interventions, the evaluation tools and models developed in this guidance also allow exploration of the constraints faced by practinionners and policy-makers when using the products of the research.
• In knowledge diffusion processes: this type of evaluation facilitates decision-making by clarifying, right from the stage of research, the factors of transferability of interventions to other contexts because the data produced are both more contextualized and based on a more comprehensive intervention logic. The results produced by means of this approach therefore appear to be more useful, more applicable, more acceptable and more readily transferable 6.

The models and tools described in this guidance therefore contribute to the development of interactive knowledge transfer, integrated into the research itself, by evaluating its perspectives, principles, modalities of implementation, and no longer simply constituting a post hoc modality of the research. The comprehensive evaluative approaches combining quantitative and qualitative method (mixed methods 7) presented in the guidance, appear to be particularly relevant for these shared analyses of interventional and policy-making processes.

In conclusion, process evaluation, as defined in the guidance, not only completes the evaluative issues of complex intervention research, but also promotes knowledge transfer right from the stage of research. Consequently, beyond methodological issues, this guidance deals directly with the challenges related to interactions between research and use of research results and encourages each of these two worlds to consider how each party can contribute to a more collaborative approach to research questions.


1. Moore GF, Audrey S, Barker M, Bond L, Bonell C, Hardeman W, Moore L, O'Cathain A, Tinati T, Wight D, Baird J. Process evaluation of complex interventions: Medical Research Council guidance. BMJ. 2015;350:h1258.
2. Campbell M, Fitzpatrick R, Haines A, et al. Framework for design and evaluation of complex interventions to improve health. BMJ 2000;321:694-96
3. Craig P, Dieppe P, Macintyre S, et al. Developing and evaluating complex interventions: the new Medical Research Council guidance. BMJ 2008;337:a1655.
4. Wang S, Moss JR, Hiller JE. Applicability and transferability of interventions in evidence-based public health. Health Promot Int. 2006;21(1):76-83.
5. Denis JL, Lomas J. Convergent evolution: the academic and policy roots of collaborative research. J Health Serv Res Policy. 2003;8 Suppl 2:1-6.
6. Cambon L, Minary L, Ridde V, Alla F. Transferability of interventions in health education: a review. BMC Public Health. 2012;12:497.
7. Guével MR, Pommier J. Mixed methods research in public health: issues and illustration. Sante Publique. 2012;24(1):23-38.

Competing interests: No competing interests

30 July 2015
Francois Alla
Linda Cambon. EHESP, Sorbonne Paris Cité, CNRS, UMR CRAPE, Rennes, France.
EA 4360 APEMAC, school of public health
Université de Lorraine, Nancy, France.