Ft Worth police officer shoots woman to death inside her home

coldseat said
That's a flawed metric, because even though we have 320 million people in this country, police certainly do not come in contact with 320 million people. It would be better to compare both numbers to the number of contacts between civilians and police (whatever that number is). As those are the opportunities where either:

a.) a police officer can be killed by a civilian
b.) a civilian can be killed by a police officer.
c.) neither is killed by the other.

Depending on what we are measuring for, it might be flawed. But with the idea of police being killed as "rare" - I don't see why your suggestion would make it better.
I mean I guess we could also try to cut down the numbers on the side of police as to interactions with violent people? So 40 out of 200,000 police officers who confronted violent people were killed? Not sure how we could measure that, or even your suggestion.