People often assume that the use of hospital emergency departments for nonurgent problems is inappropriate. To test this assumption, several questions must be answered. These include, "How do we determine what is appropriate use of an ED?"; "How can we measure urgency in the ED?"; "Is care for nonurgent problems less effective in an ED than in a primary care facility?"; and "Is nonurgent care more costly in an ED than in a primary care facility?" These four questions are addressed, and suggestions for future research that would help answer these questions are made.