BACKGROUND Care fragmentation is common and contributes to communication errors and adverse events. Handoff tools were developed to reduce the potential for these errors. Despite their widespread adoption, there is little information describing their impact on clinical work. Understanding their impact could be helpful in improving handoffs and transitions. OBJECTIVE To better understand what clinical work is done overnight, the housestaff perceptions of overnight clinical work, and how handoff instruments support this work. METHODS Real-time data collection and survey. METHODS Internal medicine resident physicians. METHODS Data collection measured information related to nighttime clinical encounters, including the information sources and actions taken. Surveys assessed resident perceptions toward care transitions. RESULTS Of 299 encounters, 289 contained complete data. The tool was used as an information source in 27.7% of encounters, whereas the information source was either the nurse or the chart in 94.4% of encounters. Many encounters resulted in a new order for a medication, whereas 3.8% resulted in documentation. In the survey data, 73.6% residents reported the sign-out procedure was safe. CONCLUSIONS These data suggest that a handoff tool is not sufficient to address nighttime clinical issues and suggest that effective care requires more than just the information transfer. It may also reflect that electronic medical records have become a readily available information source at the point of care. Sign-out should support residents' ability to make sense of what is happening and integrate care of day and night teams, rather than solely transfer information.