This article reports on a qualitative study that investigated how various risk factors associated with the process of sign-out reporting across shifts in critical care hospital environments could lead to flawed communication and thus to increased risk of poor patient outcomes. The study was performed in two critical care hospital units: the pediatric intensive care unit (PICU) and the postanesthesia care unit (PACU). We collected data from observations of eight nurses and four resident physicians in the PICU and four nurses and four resident physicians in the PACU giving sign-out reports during their shift changes. In addition, we conducted semi-structured interviews with a separate sample of medical providers consisting of nurse managers, attending physicians, nurses, and residents from each of these two units. The issues that were addressed in these interviews included how various methods of conducting sign-outs and factors such as personality and experience could impact the effectiveness of communication during sign-out reporting. We also collected data from these medical providers on how failures in communication during sign-out reporting could lead to potentially adverse patient outcomes. The article concludes with the presentation of a modeling framework that demonstrates how the combined influences of risk factors can generate a particularly important type of failure mode in communication and how interventions can be targeted to serve as barriers to such events. A number of recommendations intended for reducing risks associated with the communication of sign-out reports are also presented.