In health care systems that provide universal access to care, efforts to contain costs for standby hospital
capacity usually result in wait lists for surgical procedures. When access to health care is rationed by such
wait lists, the length of time that patients are required to wait is usually uncertain. This uncertainty is a
natural product of stochastic variation in service time and in the percentage of urgent cases in any queuing
system. However, in a queue for elective (nonemergency) procedures, waiting-time uncertainty has many
additional causes. For instance, decisions of both patients and care providers may override a queue discipline.
Alternatively, the lack of a hospital resource, such as beds in the intensive care unit, may change queuing
practices in favor of services that would not require the resource.
Waiting time is often compared between regions, hospitals, periods, or surgical services to evaluate policy and performance. However, surprisingly little attention has been given to the variation in times spent in a
single queue. Why some patients wait longer than others remains an important question in health services research. It is unclear, for example, whether time to service varies more than would be expected through chance
alone after differences in clinical condition are taken into account. Another important issue is preferential
allocation of hospital resources. It also remains unclear whether patients of low priority are admitted directly
as a way to circumvent long wait lists or to substitute for cancellations on the operating room schedule. Wait
lists for elective surgery have typically been accepted on the premise that they ensure the most efficient use
of hospital resources; the only alternative would be underutilization of capacity within the health care system. Recently, however, the debate has shifted toward the issue of how much capacity is required to maintain
safe wait lists. Policy makers have called for establishing target access times for major operations that would
minimize the adverse events associated with treatment delay.