There are just to many variables for a truly accurate comparison. Also as whit mentioned you don't get back traumatic codes, at least not long term. I did get one back, would not have not had to work but for a stupid doctor on scene. I got him back as far as heart. Intubated and aided respiratory, darted chest, etc, but pupils were blown, he never came around. Worked him again at the hospital but ER doc called it within minutes. Sorry my point is even if get them back it is not a quality return or as study "severe disability" in other words vegetable. This is not a good study to base ALS vs BLS.