Institutional review boards (IRBs) are the backbone of the ethical regulation of research with human subjects. Regulators, critics and ethicists all rely on IRBs as the primary mechanism to prevent harm and to assure the ethical quality of research. However IRBs have been bitterly criticized by researchers as bureaucratic, by ethicists as excessively focused on consent form wording, and many as ineffective. Given the important and controversial nature of IRBs, it is surprising that almost no research has been done on the processes by which they make decisions. Criticism is usually based on anecdotal accounts. The proposed study will provide a systematic description of IRB decision-making. We will attend 2 meetings of different IRB panels at ten major research institutions, studying all new protocols discussed at the meeting. In addition to observation at the meetings, we will interview the staff and reviewers about the IRB's handling of the protocols and abstract records for changes six months after the meetings. Ethnographic observations and interviews will be used to describe organizational and cultural features of each site. Systematic qualitative and quantitative analysis will provide a clearer picture of how IRBs make decisions about protocols and provide the basis for a better assessment of their functioning and of any proposed regulatory or administrative changes.