Phase IV studies are often criticized for poor scientific standards. Yet they provide an important resource for addressing evidence shortfalls in drug safety, comparative effectiveness, and real-world utility. Current research ethics policies, and contemplated revisions to them, do not provide an adequate framework for preventing social harms that result from poor post-marketing research practice. Rather than focus exclusively on the welfare and interests of human volunteers, research policies and ethics should also safeguard the integrity of the research enterprise as a system for producing reliable medical evidence. We close by briefly describing how an integrity framework might be implemented for phase IV studies.