The MRC indicates that complex interventions are usually described as those that contain several interacting components, such as an educational or rehabilitation programme. However, MRC goes on to recognise that there “are, however, several dimensions of complexity: it may be to do with the range of possible outcomes, or their variability in the target population, rather than with the number of elements in the intervention package itself.”
The trials within our complex intervention portfolio include those of ‘packages of care’ (e.g. for rehabilitation) and those aimed at changing the behaviour of health professionals, patients and members of the public. They are funded by research councils (especially MRC) and NIHR.