People who say it better than I can

Hosp Pract (Minneap). 2010 Nov;38(4):54-62. 
Improving patient outcomes from acute cardiovascular events through regionalized systems of care.

Edwards JM, Carr BG.

Department of Emergency Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.

"...Significant regional variations in practice are commonplace, and facilities with higher patient volumes of STEMI, cardiac arrest, and ischemic stroke consistently have better outcomes compared with lower-volume facilities. ..."