Emergency department crowding is an almost universal problem. Whether it is called "access block" (Austalia) or "boarding" (United States), it is seen everywhere.
The American College of Emergency Physicians (ACEP) states that "a “boarded patient” is defined as a patient who remains in the emergency department after the patient has been admitted to the facility, but has not been transferred to an inpatient unit."
It should be clear that the primary cause of overcrowding is boarding: the practice of holding patients in the emergency department after they have been admitted to the hospital, because no inpatient beds are available. This practice has been shown to have an adverse impact on patients, with longer delays causing greater morbidity and mortality.
ACEP has created resources to help address this issue, including an emergency medicine practice paper on high impact solutions. See: file:///Users/jhirshon/Downloads/EMPC_Crowding%20IP_092016%20(1).pdf
