The NIH Pragmatic Trials Collaboratory published a new chapter of its Living Textbook of Pragmatic Clinical Trials this week. The chapter, “Intervention Delivery and Complexity,” illustrates that—although an intervention may be simple—the actual delivery of the intervention may be complex due to factors such as new workflows, special training of frontline staff, and the number of components in the intervention. This chapter reviews what makes an intervention’s delivery complex and frameworks and guidance for studying complex interventions.

The chapter also highlights an online Intervention Complexity Calculator developed by the NIH Pragmatic Trials Collaboratory to evaluate the complexity of delivery of a trial intervention. To develop the tool, principal investigators of embedded pragmatic clinical trials shared critical drivers of complexity that affected their ability to implement an intervention and discern treatment effects. The tool consists of 6 domains comprised of internal and external factors that can impact complexity.

An article describing the tool and its development was also published in Contemporary Clinical Trials.