Double-damned lies and comparative statistics

It’s not as if government statistics weren’t already unreliable, but this mea culpa demonstrates why you should look very, very, very skeptically at any argument that compares the statistics from one country with the statistics from another.  Even with something as superficially straightforward as the murder rate, they simply cannot be trusted at face value:

I have frequently in this series referred to the English murder rates as historically low and currently very low compared to US murder rates.  I blandly accepted the murder statistics published by the UK Home Office as definitive.  I overlooked the details of what and how the English counted “murders.” It turns out that was a big mistake.  (I was first turned onto my error by this post at Extrano’s Alley.)

I fell into a definitions trap you may not be aware of. The shortest version is this. We count and report crimes based on initial data. The Brits count and report crimes based on the outcome of the investigation and trial. Yep, that says what I meant it to say.

In the US, the count of people murdered kept by the FBI is pretty darned straightforward. Got a body, not natural causes, not suicide? Must be murder of one sort or another. Count it.

So, if you ask the FBI, they will tell you that for 2011 there were 14,022 murders or non-negligent manslaughters.  On the same line of that chart, they tell us the population was 292,364,075 which gives us a “murder” rate of 4.8 per 100,000 population. Those counts are based on crimes reported by local police agencies.  They say nothing about the clearance rate, nor if anyone was ever identified or charged or convicted or whatever.  Body, not natural, not negligent, homicide.  Duh.

Now, on to England. It turns out that the Home office is very restrictive in what they report as “murders.”  Still, looking at the detailed report for 2010/2011 the Home office tells us that in the reporting period there were 636 murders “provisionally recorded” for a murder rate of 1.15 per 100,000 — less than 1/3 the murder rate in the US.  (See page 16 of the source document)

I’ve reported these numbers blindly many times, and quoted sources with many (sometimes silly) explanations for the lower murder rate in the UK. There’s a problem with that as it turns out. What about all those murders which were not solved? The ones where a conviction wasn’t gotten? The ones where the appeals are still on-going? Not only that, but when exactly were these homicides performed?

“Since 1967, homicide figures for England and Wales have been adjusted to exclude any cases which do not result in conviction”

OOOoooooops.  We’re not comparing apples to apples, we’re comparing apples to meatloaf. 

Keep this in mind the next time you hear someone extolling the wonders of gun laws in the UK or the excellent performance of the Scandinavian health care system.  It’s possible the statistics are relevant.  But then again, it is entirely possible that they are not.