An excellent point. Just as the same advances means there are a LOT fewer dead Americans from Iraq and Afghanistan than would have been the case in previous decades.
Murder rate is one of the few crime rates that’s more or less readily comparable across jurisdictions and decades. After all, either there’s a dead guy or not. Other crime comparisons are subject to definitional problems.
I haven’t researched it in some time, but if I remember correctly the total violent crime rate has declined in a way similar to the rate for murder. So it seems unlikely that the entire murder rate decline is an consequence of improved medical care.
For instance, the total number of violent crimes went down from 1.4M in 2008 to 1.2M in 2011, before rebounding slightly in 2012.
All the statistics are on that website and somebody can certainly thrash out whether murder has gone down faster than total violent crime. Or, indeed the opposite is also possible.
Google is amazing!
Here are the total number of violent crimes by type and rate from 1960 to 2012.
Murder went from 4.6 in 62 to 10.8 in 1980. 2012 was 4.7, which is why I said it’s possible 2013 will set a new low.
Total violent crimes, OTOH, were at 158 in 1961, and peaked at 759 in 1991. There has been a steady decline since, with 2012 at 387, which is still a good deal more than double the low in 1961.
Given that murder appears to have dropped much faster than other violent crimes, I think it’s reasonable to assign a good bit of that difference to better emergency medical care. Percentage to assign not known, and probably not really knowable.
Possibly the difference is due to fewer guns in America, and especially fewer handguns. / s
http://www.disastercenter.com/crime/uscrime.htm