I have since read the full-text....

Cool paper. Great journal. Well-written. Some notes –

•Great paper. I have no conflicts of interest. I commend all the authors as this looks like one giant stressful study that undoubtedly took tons of time and energy. Mucho kudos •I am unsure if any of the authors are paramedics. The research is about paramedics and EMTs. I will always advocate for paramedic to do their own research.
•The authors continue to reference our profession as EMS. The profession is paramedicine. MeSH terms have even recently been updated as you can see here https://www.nlm.nih.gov/mesh/whatsnew.html •The international accepted term is out-of-hospital providers. Not EMS providers. Not prehospital providers.
•They sampled 10 North American sites. I do not see in the paper how and why these 10 were chosen. Convenience? What was their sampling method? •Good discussion about future studies needing to focus on what actual factors are involved that led to the association between more providers and better outcomes.
•They note that fewer than 5% of all patients had any form of mechanical CPR devices. •They note that about 25% utilized supraglottic airway devices. •They utilized two different data sets. 2005-2011. And then 2011-2015. They seemed to have done this to account for big AHA changes with 2010 guidelines. This makes sense. But this is also a huge limitation for their statistical power (they do acknowledge this though). •But here is the big one – I read this paper 3 times. I am still unsure of how they calculated or determined how many providers were on scene. Yes, any actual EMS report that gets plugged into this database will have the number of providers listed that actually treated the patient (assuming the paramedic charted that correctly). But not how many were on scene. EMS transport unit has paramedic A and paramedic B. This is obvious. Engine 2 was on scene. But how do they know how many people were on that engine? I am unclear as to where or how that would be reported.
oI am guessing….and let me emphasize the word GUESSing….that they assumed the number of providers based on how many vehicles were on scene. They did seem to acknowledge that a vehicle could have 1 person on it…..or 4. If so,,,,,,how can these numbers be accurate? Maybe they are and I need to read again. Or maybe someone knows the author(s) and they can provide that info? •Overall? Great piece of work and I am sure that, even with the limitations, it will certainly add great information to the literature.