Maryland has a state wide trauma system and does not use ACS.
Many factors involved in evaluating, "busy."
As docB pointed out staffing plays a role. One doc for 10 new patients per hour is overwhelmingly busy. 7 docs for 10 new patients per hour not so much.
Boarding and diversion plays in as well. If you have tons of boarding patients you may be busy but not necessarily busy making emergent decisions. Also, the amount of time spent on diversion will play a role in how often the critically ill patients can get to you (not that they never come from the waiting room, but certainly a greater frequency from EMS).
Ancillary support can shape your sensation of busy. If you have to draw the blood yourself and label everything and run the samples to the lab and transport the patient, well three patients per hour may keep you overwhelmed an entire shift. Whereas, if you have support for all those tasks but have 6 new patients per hour may result in the same sense of being overwhelmed but result in different experience altogether.
The admission process shapes your perception of busy. The more convoluted the processes within your hospital (more phone calls, more hassles, more delays) can result in more busy work for you and a sensation of being busy even with fewer patients.
The EMR will impact you in much the same way
The complexity of your patients factors in as well. we can see 20 ankle sprains per hour in healthy individuals, but 20 people with chest pain, dyspnea, and abdominal pain in patients with numerous cancers, heart diseases, medications, and exposures is much more difficult.
I'm sure these things are obvious but I thought I would mention them anyway...
