In order for statistics developed by someone else to have relevance to a question
you wish to ask, you have to consider the purpose for which the statistics were gathered the first place. Then, you have to consider how they interpreted their data.
Even the FBI cautions against trying to interpret the results of its cumulative UCR/LEOKA data sets and thinking to apply it to "answering" questions it hasn't asked, and trying to apply it to some specific geographical location.
Now, firearms trainers in LE sometimes have it a bit easier, because they can look at a growing body of available incident data (as general or as narrow as they feel appropriate) and
use it to learn to ask better questions.
Instead of attempting to apply it in some "predictive" manner (good luck with
that), they can look for commonalities of factors and conditions of documented incidents in ways that might help them ask better questions about how to design their training goals to hopefully to better prepare their people for OIS situations they feel are the greatest "typical threat" facing their people.
Instead of just looking at "gear-centric" influences, meaning "things" that come out of a box or package, how might they adjust their focus and training emphasis and efforts in ways that might serve as "multipliers", and help their people become better able to apply the particulars of the "lessons" of their training across a wider range of potential situations and circumstances? Awareness? Adaptability? Revisit policies and procedures? Keep better abreast of the changing legal landscape (like case law)? Raise the bar of what's considered "acceptable competency"?
It's not as simple as thinking to create cut 'n paste tactics for 1 attacker, 2 attackers, 3 attackers ... an attacker with a pistol versus an "assault weapon", an attacker possibly on drugs, or suffering a mental health episode, etc.
There are a lot of pretty good reasons why LE trainers have agreed that each and every OIS incident is virtually unique. It may share some of the basic common elements (attacker, threat of serious injury or death, a chaotic & rapidly evolving situation, etc) ... but the chances of
everything lining up to repeat itself in other incidents is a real stretch.
What can their trained people
do with their gear, and the knowledge, training and experiential knowledge they may have gained (more time on the job learning to successfully apply their knowledge and training), etc?
What are they going to require as a minimum level of demonstrable adequacy and competency, and how do they decide to effectively assess and measure that? How to document it?
Private trainers? Well, obviously they may have their own previous experience and knowledge (professional local, state or fed backgrounds), as well as any acquired information based upon what they've learned to be the actions of their "students" post-training. Then, there's their own personal preferences and any desire to look at the type of data they may decide to collate and interpret into "statistics" as they wish.
Me? I'm the inevitable product of my years of LE training and experience (seeing crimes that occurred in my area of responsibility, and learning of it from cops and trainers in neighboring jurisdictions throughout those years) ...
and being exposed to ongoing LE-based training required as part of my responsibilities of having been a LE firearms trainer for a fair number of years. When the cops I helped train asked me a question, if I didn't have the answer, I was expected to start looking for one (which meant knowing
where to start looking for one). If the
wrong question was being asked, I was expected to be able to explain
why it was the wrong question, too.
Then, there's the personal effort to continue to learn of such things outside of what I was required (and able) to learn as part of my job. A good instructor never stops being a student, right? It's been that way in my lifelong martial arts pursuit, so why would being a firearms trainer - and user/student - be any different?
I try to tell people I've helped train to avoid becoming lost within the data. What are you trying to prepare for? Is it a realistic situation to anticipate? Has previous or current training been useful? Can we adjust training to make it more effective to address the "new question"? Are we distracting ourselves from more critical questions and issues? Have we gone down
the rabbit hole?
Statistics? Especially "reliable gun statistics"? How about Polls?
Learn your firearm, including its maker-recommended maintenance and service intervals, and any associated gear (holster, including its safe & proper use, as well as recommended care and maintenance). Learn the laws related to the use-of-(deadly)force, especially the use of firearms in your jurisdiction (or any one you intend to visit).
If you require some legal advice specific to your concerns and activities, consider going to pay for some (attorneys usually charge for their services, right?). Police enforce the law, they don't practice it (although I've known my fair share of cops who also had law degrees and were licensed attorneys, as a sideline).
Just some personal thoughts.
Luck to you.