I'm not sure what the "right" number is, but you would expect that someone trained to use a weapon would "win" in the majority, if not the vast majority of case

I'm not sure what the "right" number is, but you would expect that someone trained to use a weapon would "win" in the majority, if not the vast majority of cases. The ideal ratio would be zero police deaths compared to a much smaller and truly unavoidable number of civilian deaths, but even in that ideal case, the ratio would be incredibly skewed toward civilian deaths, so perhaps this number doesn't tell us much.