Achieving a positive safety culture requires that all team members feel comfortable voicing safety concerns. Hierarchy and poor communication are well-recognized barriers that prevent team members from speaking up about safety concerns. In this qualitative study across 19 intensive care units, researchers used data from hundreds of hours of ethnographic observation and interviews to understand how team members raised safety concerns and to characterize processes of social control exercised in response to mistakes, perceived safety risks, and deviations from normal practice. The authors argue that a better understanding of social control is necessary to facilitate voicing safety concerns in the clinical setting. A past WebM&M commentary discussed an incident involving a medical student who did not speak up when a urinary catheter was inserted without sterile technique.