Complex interventions Methodological challenges in their systematic development and evaluation

Critical appraisal of a randomised controlled trial is a comparably simple task. Different guidelines and checklists are available. However, it becomes problematic if the trial intervention consists of multiple components. Such interventions are called complex interventions. For instance, structured educational programmes are complex interventions as they incorporate interdependent components, such as contents, media and methods. Systematic evaluation of complex interventions is a methodological endeavour. Interdependencies of multiple components must be considered in the light of varying implementation contexts.