Evaluating complex interventions

There is an increasing interest in evaluating complex interventions. This is because epidemiological changes increasingly call for composite interventions to address patients’ needs and preferences. It is also because such interventions increasingly require explicit reimbursement decisions. That was not the case in the past, when these interventions often entered the benefit package automatically, once they were considered standard medical practice. Nowadays, payers as well as care providers are intrigued to know not just if a health care intervention works but also when, for whom, how, and under which circumstances. In addition, there is broad recognition in the research community that evaluating complex interventions is a challenging task that requires adequate methods and scientific approaches. This chapter describes what an complex intervention is, discusses the rational for and challenges in the evaluation of complex interventions, and provides an overview of evaluation steps and methods