On terrorist probabilities

Why aren't the Scots doing more to combat their culture of violence? Why aren't its community leaders doing more to rein in their violent minority? Don't we need tougher laws to protect us from the threat posed by men of Scottish appearance?

You might think I've lost my mind. From a statistical point of view, though, I haven't.

According to table 1.18 of this pdf, there were 89 Muslims in prison for terrorist offences in March 2012 . As there are 2.7 million Muslims, this is 33 per million.

By contrast, there were at the latest count 2382 people imprisoned in Scotland for assault or murder. That's 449 per million.

The prevalence of violent people in Scotland is therefore 13.6 times that of terrorists among Muslims. In fact, this is an understatement. A Scotsman who has committed a violent crime is more likely to be out of prison than a Muslim terrorist, either because he's more likely to have gotten away with his crime or because he's more likely to have finished his sentence.

If it is reasonable to speak of a problem of Muslim terrorism, it is therefore an order of magnitude more reasonable to speak of a problem of Scottish violence.

I anticipate two objections here.

One is that terrorism is nastier than street fights. True.But we must distinguish between the cost of an event and it's probability; I'm talking about the latter.

Secondly, the prevalence of terrorism is greater among Muslims than non-Muslims; Nick Cohen is correct to point out that popular culture misrepresents terrorism in this regard. We can quantify this. There are 29 non-Muslims in prison for terrorist offences. That's a rate of 0.5 per million non-Muslims in the population generally. So, Muslims are more likely to be terrorists than non-Muslims. Coincidentally, the difference between the two groups is about the same (pdf) as that between the prevalence of assault in Scotland and New Zealand - so my analogy holds.

But of course, P(A|B) is not the same as P(B|A). The fact that a terrorist is likely to be a Muslim does not mean a Muslim is likely to be a terrorist. Even if we assume that there are ten terrorists walking the streets for every one inside, then 99.988% of Muslims are not terrorists. To put this another way, there's only around a one in 8000 chance of a Muslim being a terrorist; it's 16 times more likely that the Duke and Duchess of Cambridge will name their child Wayne.

Given all this, why does anyone think terrorism is a Muslim problem? There are several biases at work:

1. The out-group homogeneity bias. Will Davies tweeted that "in my day, a bloke who stabs a random stranger then rants about the government was called 'insane'". This is true if the bloke is one of "us". If, however, he is one of "them" then he is more representative of "them".

2. The narrative fallacy. We love to tell stories and read messages into things, and thus underweight the significance of random nuttery. Frank Furedi says:      

One problem with the construction of the random fanatic, is that virtually any form of incomphrehensible act of violence – a school shooting, a crazed knife attack – can be redefined as an act of political terrorism. That is why far too many people cannot resist the temptation of defining the tragedy in Woolwich as an act of political terrorism.

3. The availability heuristic. Dramatic events weigh heavily upon our mind, and this causes us to overweight their probability.  

4. Many groups have an incentive to exaggerate the significance of terrorism, and to reframe insane violence as "terrorism." For the police, such attacks give them a chance to further inflate their sense of self-importance and to seize more powers. And politicians can use the image of grave danger and an evil foe to appear Churchillian.

Some things, however, are less significant than they seem.

Comments

[BenSix]

It would be presumptuous to dismiss them as insane because *we* can think of no rationale for their behaviour. Jihadists have a long tradition of beheading.

http://www.tandfonline.com/doi/pdf/10.1080/10576100701200140

Terrorism by Muslims can be a "Muslim problem" because it is so influenced by currents in Islamic thought. I have no more of an idea of what influenced these men than Frank Furedi does but it could very well be the ideas of defensive and offensive jihad.

[ortega]

Spot on.
Pity you chose scots as example, because the irish did kill a lot of people for not being irish (or not irish enough), wich is not exactly the case with the scots, and really nobody noticed.

[FromArseToElbow]

@Ortega, "the irish did kill a lot of people for not being irish (or not irish enough)". Almost every word in that a sentence is factually wrong, but let's not pass up an opportunity to slur the green supremacist bastards.

[Luis Enrique]

is this quite the right way to look at this?

suppose there was one werewolf in this country that roughly once a month devoured a random person.

all of us would face higher probabilities of being killed falling down stairs, choking on peanuts etc. than being devoured by this werewolf.

1. I don't think it's irrational/biased/fallacious to be more scared of that werewolf than stairs and peanuts. Werewolfs are scary!

2. I'd be happy for the state of exert considerable effort catching that werewolf.

[All hail diversity!]

Terrorism is a "Muslim problem" because there is direct and unambiguous Quranic justification for these acts. That relatively few people act upon that scripture is neither here nor there.

I'm not quite sure why people say that violent Islam is not "real" Islam. Sunni, Shiite, Sufi, Wahhabi, violent, non-violent. These are all as "real" as each other. And this is what happens when we import primitive desert tribalism en masse. Still, at least we're "diverse", eh?

[chris]

@ Ben, AHD. OK, so there are violent strands of Islamic thought. But so what? There are violent strands of (eg) Marxist or conservative thought. Thought shouldn't be a crime. The fact that so few Muslims are terrorists shows that such thought rarely leads to action.

[All hail diversity!]

@ Chris.

It isn't "thought" that's the problem, evidently. And "rarely" is too often.

If you leave your front door open every day, and one day you get burgled, you don't say "well it doesn't matter, I leave my front door open every day and I only get burgled rarely so I'll keep leaving it open". No. You lock your door.

[Nick]

"suppose there was one werewolf in this country that roughly once a month devoured a random person...

2. I'd be happy for the state of exert considerable effort catching that werewolf."

That would make a lot of sense because a single large cost would prevent lots of future deaths in the months and years ahead. If (magically) catching a warewolf always led to another warewolf popping up, then it wouldn't make so much sense. We would want to look into the root causes of the warewolf instead (presumably some sort of curse!).

[All hail diversity!]

@ Nick

A "curse" known as Islamic immigration.

[Chris Purnell]

A magnificent piece of statistical literacy elegantly written.

[aragon]

Chris is playing fast and loose with statistics.

As others have pointed out generalised violence in society is different from ideologically driven terrorism.

Four Terrorists killed fifty two and injured seven hundred people on 7/7/2005 in London, and none of the four are in Jail. (not to mention thousands of deaths at 9/11/2001 in New York)

How does that distort your figures ?

Terrorism often aspires to mass murder and mass injuries. It is by nature different.

Also what about non-terrorism acts of murders by Muslims (how does assaults get into this argument ?), if you wish to compare levels of violence in society.

The truth is that Chris is abusing statistics comparing fundamentally different issues and been selective in the choice of statistics.

Which meets my low expectations.

[Luke]

Do you have a differing opinion about terrorism vs random violence depending pn whether you live in a crowded place? There may be random violence in London, but there's plenty of other targets than me. But no one (famous last words) will plant a bomb in a village in Lincolnshire, whereas the Tube at 8.45am is more of a target.

[Keith]

The problem with this argument is that we feel more threat from a ruthless Islamic nut than from a alcoholic Scotsman.

Unless you live in Scotland you have no need to worry about them; and Scots neds are only following cultural practices that are diffuse. Islamic nuts are politically motivated and have exact targets based on their theory of politics. We have no strong feelings about Scots men beating up or murdering their wives but feel the threat of Fanatics. So that is a bad thing that we care so little for the victims of drunk Scotsmen or for the welfare of the Scotsmen who clearly need help.

The main problem is that the Popular remedies for Terrorism do not work. Anti Terrorism Legislation just undermines civil Liberties. There is no justification for reducing the rights every one enjoys because some people commit criminal acts. People are entitled in a Liberal Democracy to believe in any view however extreme. Believing in extreme ideas is not a crime and most of the people who hold extreme ideas will not kill any one. It is impractical for MI5 to follow every nut around for years just in case.

[CJRH]

You don't account for the nature of the high violence in Scotland by Scottish people. You don't account for sociological issue encountered by the increasing numbers of young people who are on the fringes of Scottish and British politics.

I have no doubt Muslims are less violent, it's a drilled in part of their culture and most are certainly not afraid of that, but what people are afraid of is extremism, not misguided, drunken youths.

You quote the correct numbers and you make good points, but you don't get to the heart of the matter because your evidence is biased and has confused causation and correlation.

I believe the media are too quick to jump on the old "them" and "us" train, but that's very much what the situation is. I have lived abroad and i paid a great deal of attention to fitting in and following the customs of that country.

An imam on the BBC summed it up perfectly (i paraphrase his comments) - If you want change, go into politics and become involved at the local levels. If you hate the UK, hand your passport in and leave. If you're doing it to get into heaven or impress the Muslim community, neither will happen.

I have many Muslim friends who count themselves as proud Scots and Brits. They have spent time fitting in here.

[shtove]

@keith
"The problem with this argument is that we feel more threat from a ruthless Islamic nut than from a alcoholic Scotsman."

You're begging the question.

The probably reason we may feel more threat is because we're not viewing the problem statistically.

In any case, I can't see why everybody didn't immediately conclude that the cleaver killers were just deluded nutters.
A one-off murder by people who wanted attention and to be caught in the act. Watching too much Chechclear.

Perhaps because BBC etc ran with the breaking news banner that the police were "treating the matter as terror related".

[Melissa]

The running down and hacking death of a British Army soldier is NOT a tragedy, it is a MURDER. Words have meaning.

[Neil]

I think people actually ARE afraid of aggressively drunk Scotsmen, as they are of aggressive drunks in general.

Also, I can't help but think that if circumstances were slightly different, we'd be talking about the effects of crack cocaine and/or crystal meth.

[Ralph Musgrave]

Aragon is right: Chris is playing fast and loose with statistics. In particular Chris compares the number of Muslim terrorist offences with a much more common and completely different crime: “assault or murder” by Scots.

You might as well argue there are far more cases per million of the population of speeding offences in England than there are cases per million in Scotland of murder, which proves the English are less law abiding than Scots.

Moreover, terrorism by Muslims has a political or religious objective: imposing an utterly disgusting and backward philosophy on the host countries. The various disgusting characteristics of Islam are too many to list, but they include prosecuting women for the “crime” of being raped, killing the cartoonists and authors one doesn’t like, homophobia, holocaust denial, etc.

I’d rather have a hundred drunk and abusive Scots in my neighbourhood than one Jihadist.

But of course the political left is not bothered by the above mentioned and fundamentally uncivilised aspects of Islam.

[Boursin]

"The running down and hacking death of a British Army soldier is NOT a tragedy, it is a MURDER. Words have meaning."

So all the great tragedies of Western literature that involve murder are mistitled?

"Mr. Shakespeare, the cornering and stabbing of Julius Caesar is NOT a tragedy, it is a MURDER. Words have meaning."

[Neil]

"I’d rather have a hundred drunk and abusive Scots in my neighbourhood than one Jihadist."

How would you know? Would you knock every door and ask?

[guthrie]

Why yes, thanks for asking, we are doing lots of reign in our culture of violence.
See for instance the Violence reduction unit in Glasgow, and the work done on reducing violence at football matches and sectarian incidents.

But it's all mince anyway, since you haven't included the ratio of Scots in prison for terrorism charges, and ratio of muslims in prison for violence or murder.

[Mitch]

@guthrie - hear, hear! Glad someone is standing up for the Scots.
Comparing Islamic terrorists to Scots in jail for violence offences is comparing apples with oranges. As Guthrie says, the article does not include the ratio of Scots in prison for terrorism charges, and ratio of Muslims in prison for violence or murder.
How about looking at the threat of violence per head of population in England or the UK as a whole? Why single out Scotland? England has just as many violent alcoholics languishing in jail.
The article, actually, does not mention alcoholic Scotsmen, this was first mentioned in a small-minded comment from Keith. There are 5 million Scots living in Scotland. We cannot all be alcoholic or violent or men, for that matter.
I suggest you stop looking for sensationalist headlines that alienate a section of the population unless you can back it up with a solid argument.

[Luke]

Mitch, I don't think Chris was particularly picking on the
Scots - just a handy comparison with stats available. People
from Manchester would have done. Or left handers if figures were available. If you're feeling a bit picked on, fair enough, but imagine if your name was Mo...

[Churm Rincewind]

"There are 29 non-Muslims in prison for terrorist offences. That's a rate of 0.5 per million non-Muslims in the population generally. So, Muslims are more likely to be terrorists than non-Muslims."

There are 81,000 blacks in prison in the US, amounting to 35% of the prison population. Yet blacks only comprise 13% of the general population. So, blacks are more likely to be criminals than whites.

While this may be literally true, I really don't think it's a particularly revealing analysis of black culture. Could it be, for example, that blacks are more likely to be criminalised than whites?

There are lies, damn lies, etc...

[Staberinde]

If the Woolwich murderers are 'nutters', then the question becomes "What was the form of their mental illness and how do we prevent more people acquiring it?"

It strikes me that the answer is a genuine belief in the fantastical in general, in religion specifically, and extreme Islam particularly. And we might start by withdrawing State funding for faith schools and challenging the belief-set in the same way society challenges racism, sexism and homophobia.

On the statistics argument, it is a case of apples vs. oranges. I might be struck by lightning or I might be hacked to death in the street by a religious nutcase. But one is an act of God and the other the act of a God-botherer. And I rather expect the State to do something about the latter.

[Arjay]

Haha. I woke up down today. You've chereed me up!

[nb]

This is really a great example of obfuscation by means of statistics - "Lies, damn lies and statistics".

Chris asks why anyone should think that terrorism is a muslim problem. The reason is the point that he hurries by rather quickly - the fact that most terrorist acts are indeed committed by muslims.

One can use Bayes Rule and the data that Chris cites to calculate P(M|T), i.e. the probability that the terrorist perpetrator is a muslim given that a terrorist act has occurred. By my calculation that probability is about 75%.

Surely that is plenty of reason to think that terrorism is a muslim problem! It's also a fact with large practical implications for policy. For example, if you want to preempt terrorism, or to catch its perpetrators, you would do well to focus your surveillance on muslims. That's a very un-PC conclusion, of course. But it is precisely the policy implemented by any serious anti-terrorist intelligence service.

[Lexus]

I read your post and wished I'd wrttein it

[SteveH]

If you discount from terrorism the mountain of corpses created by the British and US imperialist forces and regard terrorism as those acts committed against the interests of Western imperialism then I guess you can certainly say most terrorism is Muslim related.

Otherwise we can safely say that most terrorism is committed by white Westerners and Muslims are simply reacting.