Wednesday, March 30, 2011

Capital punishment in 2010

The Guardian published an infographic based on statistics Amnesty International compiled on the number of death sentences and executions, by country for the last four years. It's a very pretty picture, but I felt that there was something missing; you might suggest that China gets a bad rap, but because it's much bigger than any other country except India, of course it's going to have a higher execution rate.

It's said that a liberal is just a conservative who hasn't been mugged yet; I wonder if my opposition to the death penalty is because I haven't suffered from any crimes yet where I'd want the perpetrator to be killed. I've been fortunate; of all my friends and family, I only know of one person to be affected by violent crime. I'll return to that later, but first I wanted to use data to try to examine some of my prejudices about where and why capital punishment was popular. Well, frequent might be a better word.

Handily, The Guardian will let you take the data they've got and put it into your own visualisation tools, and although Wikipedia isn't a perfectly trustworthy source, for a fast and dirty bit of work, it's an easy place to get the population and GDP statistics for every country in the world.

Unfortunately, you find at this point the two sources aren't in complete agreement so you have to do some cleaning to align them - for example, Taiwan and China are named differently in Wikipedia and on the Guardian's site, as are various other countries (the Congo, South Korea vs Korea, South and so on). This isn't too difficult a stage to get through with this small number of data points, though. Would have been nice if Tableau could clean it for us, but perhaps we can't expect a tool to do all the work for us.

Then we feed it into Tableau Public, and that gives us a handy scatter graph like this:

Another handy way to illustrate the differences is to look at a graph of death sentences per million people, vs GDP per capita PPP (trying to adjust the GDP per person to account for the variable pricing power of different currencies):
Because you don't have to hover over each point to see which country it is, the graphs can make it easier to spot differences between how prosperous a country is, and how keen the judiciary are on putting people to death. Although the US and China get mentioned by the Guardian article, there was no mention there of Singapore's high sentencing, and this in a country with a higher GDP per capita than the US (and higher than those hydrocarbon rich Arab states, although they're far ahead when it comes to sentencing people to death). Being prosperous isn't a guarantee that you don't like killing people, even if you wanted to believe that death sentences are more likely in poorer countries that (taking a traditionalist, Euro-centric view) just aren't civilised enough yet to afford to not kill people. Morality isn't a luxury item after all, or it's one not everyone buys.

The first time I looked through this data, I was surprised that Russia didn't feature higher. That was until I did some more research and saw that there's currently no death penalty in Russia. Which, if you thought the US is a beacon of liberty and democracy, and Russia is a mafia-run oligarchy, wouldn't it be a bit odd that the former has a death penalty and the latter doesn't?

Or is it to do with the opportunity to irradiate spies, murder journalists and pump poison gas into a theatre full of hostages if there's terrorists in there, without requiring judicial process? One of my Chinese friends suggested it was just that in Russia people could be 'disappeared', so a death penalty is superfluous. Meanwhile in China, they're a bit more organised - supposedly your family gets a bill for the bullets after you're executed.

Not that China is organised enough to release statistics on the productivity of their firing squads. Amnesty can only say 'thousands' were sentenced and executed, and depending on whether 'thousands' means 2,000 or 10,000, China moves up and down the ranks of countries most frequently executing people.

As I said near the start, another problem is that this data doesn't index all the violence in the world, just a small subset of it, as visited by the State upon individuals. If somebody is killed by a criminal, that doesn't show up here. If people are murdered by a rampaging mob, or a militia that the government allows to operate, then even if the government tacitly sanctions this, they won't show up here - shootings in Bahrain recently or the violence in Libya just won't show up. Perhaps these are things we have to ignore; the death sentences measure how violent the judiciary is in 'normal' situations. Effectively, that's the best we can hope for, and if the government is busily engaged in murdering thousands under sports stadiums or dropping people out of helicopters, then analysing these stats is really not going to guide policy at all.

What might be more interesting, and it's regrettable I haven't had a chance to crunch any numbers on this, is whether the death penalty serves as a good deterrent. We only have four years worth of sentences and executions; perhaps if we could trend this over a longer period, or look at the crime rate across the US for states with and without the death penalty, that might teach us something about whether removing the death penalty does impact on the misery of the world or not.

Again, there are all sorts of questions about whether reported crime rates can adequately measure the actual level of crime, but an approximate answer to an exact question is better than an exact answer to an approximate question; you have to make up your own mind what's approximate in this case and what's exact. For all the bad things that the Labour government in Britain might have done, they did at least have faith in numbers to guide policy. Too much faith in statistics as an alternative to common-sense can lead to some terrible mistakes too, but the more data we can get (and interrelate), the better off we may be when pondering these things.


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