The assessment of the response of a prehospital/hospital system to a disaster will prove a complex and challenging undertaking for those who attempt it. Data availability and quality will prove to be an immediate problem. Finding the time to devote to assessment is usually difficult. Identifying qualified and interested members of the required multidisciplinary team and, in particular, an individual with health services research background who can assist in all phases of the design and implementation of the project, is often difficult. Obviously, these problems will be less severe if they are addressed to some degree in the disaster plan. That is, a general protocol for assessment could be developed as part of the disaster planning effort and evaluation staff could tentatively be identified by position (e.g., emergency department medical director). The issue of data availability could be confronted and provisions made for the recording of at least minimal information on patient log forms under disaster conditions.