Institutional review boards are almost universally considered to be overworked and understaffed. They also require substantial commitments of time and resources from their members. Although some surveys report average IRB memberships of 15 people or more, federal regulations require only five. We present data on IRB meetings at eight of the top 25 academic medical centers in the United States funded by the National Institutes of Health. These data indicate substantial contributions from primary reviewers and chairs during protocol discussions but (...) little from other members, which implies that it may be possible for smaller IRBs to accomplish the same tasks with no reduction in the quality of review. (shrink)