• bioterrorism
• emergency department overcrowding

In this issue of the journal,¹ Fatovich and Hirsch report on the ambulance bypass experience of one hospital in Western Australia from 1999 to 2001. Like in other jurisdictions,^2–,⁴ ambulance bypass has become more frequent reflecting worsening overcrowding in emergency departments (ED). Of particular interest are the insights of ED staff who recorded their perceptions of the main causes of overcrowding at the time an ambulance bypass was initiated. Not surprisingly, the great majority of bypass episodes resulted from excess patient volume, including too many new patients presenting in a short period of time for care, an inability to move admitted patients out of the ED to ward beds fast enough, or both. Other causes, including facility problems, staff shortages, an excess of high acuity patients, or external disasters were much less common.

For physicians working in most EDs in the UK, Canada, or the USA, the fact that Australia is also experiencing worsened ED overcrowding will come as no great surprise. But if a similar problem exists in another part of the world, are the important causes necessarily the same as those close to home? In other words, can we assume that the Australian experience is directly relevant to our own?

ED overcrowding strikes hospital systems, not patients, thus the comparability of those systems is of paramount importance when comparing the problem in different settings. Unlike illnesses such as acute myocardial infarction where predictors like age, sex, or diabetes have straightforward definitions, the predictors of ED overcrowding are largely logistical in origin. The usual causes include …