Let me start by saying to all, thank you for the civil discussion on this and keeping this thread open with something that is important to all of us pro 2A folks, it definitely applies to all of us.
I've read a few articles over the past few years on this. Exactly what is stated above. There is no standard for reporting shootings or uses of force nationwide. Only fatalities are noted and even then, they are not necessarily separated as "officer involved", often just listed as homicide (the definition...not the same a murder). I think we all agree it would be helpful to have better statistical reporting in this area. Specifically being able to track the "why" behind what happened to improve training and other areas when working with the public.
Sadly, excusable is a standard. We are judged by the doctrine of the reasonable person. Life in these fringes is gritty, fraught with danger for both side almost always with limited or incorrect (an the time) information. Most people go through life either never or only extremely rarely experiencing this. They are nearly always only along for the ride when they do, not having to make life or death decisions.
By nature of the job, officers are frequently placed in these positions. Under the same conditions, knowing what they know (including training), if another officer would have found it reasonable to have the same action it will be ruled to not be a criminal action. This is how those of us who carry weapons for personal self defense will be judged as well. There is a phrase that sums it up (not mine), awful but lawful.
This is why, as some of you have noticed from posts in other threads, that I'm pretty much a zealot for us who carry firearms to have as much quality and documented training as possible. Heaven forbid any of us have to use deadly force and a legal case is brought against us, even knowing what we did was justified (different from excusable), we are allowed to show what the "reasonable person" looks like to us.
The officer's "reasonable person" includes all academy training, advanced officer training and, most importantly, typically years of experience of what really happens during violent encounters.
These discussions always lead to the same place, the same kind of posts needing to be repeated or explained over and over and over. I long for the days when we appreciated the service and risks of our LE brothers. Not to say that all LE is perfect, but it saddens me that the general attitude appears to have degenerated into "Ya filthy Screw!".