Principal investigators have an ethical obligation to develop a data and safety monitoring plan that includes an appropriate mechanism to monitor for changes to the risk-benefit balance and for data integrity during the course of a clinical trial. The purpose of this monitoring is threefold: to protect the welfare of participants in the trial, to protect patients who have the same clinical condition outside the trial, and to ensure that the trial results will be informative.

The data and safety monitoring plan must be described in the research protocol and approved by the institutional review board (IRB). There are several approaches to consider: an independent data and safety monitoring board (DSMB; also referred to as a data monitoring committee); designation of a single independent monitor; or simply a documented plan for how and when a designated study team member will monitor study conduct and results. Selection of a specific plan will depend on the characteristics of the study itself, including the level of research risk, the vulnerability of the study population, and the size and complexity of the study.

In this chapter, we discuss issues related to data monitoring that may pose particular challenges in the context of pragmatic clinical trials embedded in healthcare systems. These issues are important to consider before study initiation to ensure that an appropriate data and safety monitoring plan is in place—one that balances the pragmatic nature of the trial with the need to maintain trial safety, validity, and integrity (Ellenberg et al 2015).