During disasters, several steps may need to be conducted simultaneously when planning a surveillance system. Just as purpose and objective should be clear in any disaster response effort, the surveillance system must also have well-defined objectives. Additionally, data sources need to be identified and selected. Although facility-based surveillance of hospitals and emergency medical operations can provide information on those seeking care during a disaster, additional nontraditional sources of information may also be required (such as a shelter, pharmacies, or physician offices). Ideally, data collection instruments for surveillance should be developed, tested, and distributed before the disaster occurs. However, these instruments will need to be modified for each disaster and location. The data collection instrument should collect only the most essential information and involve easy data entry. For information to be useful, it must be disseminated in a timely fashion through the appropriate channels (e.g., public health and other government officials, relief workers, the affected community, and the media).