Official websites use. Share sensitive information only on official, secure websites. Evaluating complex interventions is complicated. The Medical Research Council's evaluation framework brought welcome clarity to the task. Now the council has updated its guidance. Complex interventions are widely used in the health service, in public health practice, and in areas of social policy that have important health consequences, such as education, transport, and housing.
They present various problems for evaluators, in addition to the practical and methodological difficulties that any successful evaluation must overcome. In , the Medical Research Council MRC published a framework 1 to help researchers and research funders to recognise and adopt appropriate methods. The framework has been highly influential, and the accompanying BMJ paper is widely cited.
This has now been incorporated in comprehensively revised and updated guidance recently released by the MRC www. In this article we summarise the issues that prompted the revision and the key messages of the new guidance. The Medical Research Council guidance for the evaluation of complex interventions has been revised and updated. The process of developing and evaluating a complex intervention has several phases, although they may not follow a linear sequence.
Experimental designs are preferred to observational designs in most circumstances, but are not always practicable. Complex interventions may work best if tailored to local circumstances rather than being completely standardised.
Reports of studies should include a detailed description of the intervention to enable replication, evidence synthesis, and wider implementation. As experience of evaluating complex interventions has accumulated since the framework was published, interest in the methodology has also grown. Several recent papers have identified limitations in the framework, recommending, for example, greater attention to early phase piloting and development work, 3 a less linear model of evaluation process, 4 integration of process and outcome evaluation, 5 recognition that complex interventions may work best if they are tailored to local contexts rather than completely standardised, 6 and greater use of the insights provided by the theory of complex adaptive systems.
