Complexity of the intervention

While we intuitively sense that psychological or social care interventions are more complex than prescribing a drug, there is no clear dividing line between complex and noncomplex interventions. The term is to some extent subjective, and there may be disagreement as to whether a particular intervention is complex or not, or whether it is very complex or mildly so. We can generalize by saying that a complex intervention must include several components that act both independently and in interaction with others. The complexity of an intervention increases with the number of components,