After the atrocities in Paris last night, it may seem the wrong time to talk about statistics, yet much of the subsequent commentary has involved statistical considerations, albeit implicit. A common concern is that because the terrorists chanted Islamic slogans it might be interpreted as proving that all Muslims are terrorists. Hence the frequent explanations that not all Muslims are terrorists. If anyone draws that conclusion, they would of course be mistaken.
Most Muslims are not suicide bombers.
However, that does not end the statistical discussion, because there is another statement which is equally true.
Most suicide bombers are Muslims.
The following commentary on those two observations is hardly snappy, but it covers the observed facts: Most Muslims are not suicide bombers. Suicide bombers are a statistical rarity among Muslims. However, if you look at the last 20 years of suicide bombing (people with bombs strapped to their bodies, who may also carry other weapons with which they kill members of the general public) then the majority are Muslim. Yes, those deaths are few when compared to other deaths, including violent deaths, but these murders have a particular extra sting of intentionality: they are conducted at random against people for for simply being what they are: civilians going about their lives.
People are not fools. They can understand the normal processes of disease, and of the accidents that sometimes happen. They understand that national murder figures include criminals fighting each other over territory. They find it much harder to accept being attacked by someone bent on the pitiless destruction of their society. Hence the reason why members of the public are often alarmed by militant Muslims, fear them, and want to avoid them. They do so fully knowing that most Muslims are not terrorists and also knowing that most political, random violence attacks against them are carried out by Muslim terrorists. Being Muslim is a distinguishing characteristic of contemporary terrorism directed against the West. It is very, very weakly predictive, but it is not zero, and people tend to think in general categories, not in statistical gradations.
During what were euphemistically referred to as The Troubles, the mainland bombings and gun attacks on the United Kingdom were carried out by Nationalist, Northern Ireland Roman Catholics with Irish Republican Army membership. Their being Christians, at least nominally, was not a distinguishing feature, though Roman Catholicism in Northern Ireland was arguably a relevant aspect of their upbringing. (Schooling was largely religiously segregated). British citizens were variously worried about Catholics, nationalists, and the Irish in general. They knew the bombers were a minority. They suspected that they had covert support from many Catholics in Northern Ireland, and big turnouts at IRA funerals seemed to confirm that. Irish accents were not a prized characteristic.
Political murders aside, the proportions of murderers vary considerably from one nation to another. Murder rates per million range from 3 in Japan, to 10 in the United Kingdom and France, roughly 20 in North Africa and Middle East (Syria before the war 22), 30 in Taiwan, 40 in Fiji, 50 in Mauritania, 61 in Ghana, 71 in Eritrea, 80 in Eastern Africa, 90 in Russia, 100 in Middle Africa, 111 in Madagascar, 120 in Ethiopia, 133 in Grenada, 147 in the Cayman Islands, 152 in Myanmar, 170 in Guyana, 184 in Botswana, 193 in Equatorial Guinea, 200 in Nigeria, and then upwards through the Caribbean, Africa and Central America, till we get to 308 in Columbia, 412 in El Salvador, 526 in US Virgin Islands, 537 in Venezuela, and 904 in Honduras.
Not everyone in Honduras is a murderer (merely 1 in 1106 Hondurans), but there is an appreciable 300 fold increase in the risk of being murdered when compared with Japan. You are perfectly entitled to avoid Honduras and holiday elsewhere. Indeed, it is up to you at precisely what murder rate you choose not to visit a country. As an adult you can set your own risk preferences, and act accordingly.
To get things into proportion, this new attack on Paris is a very significant event. Some reports say that the perpetrators clearly had French accents. That is also very significant. The wider issues of the slaughter in Paris were prefigured in January, with the attack on journalists and a Jewish supermarket.
I said then: Islam has a prominent militant wing, a death meme which finds resonance in many a self-important young idiot.
I do not know how one achieves a Reformation in fundamentalist Islamic beliefs, or even if that is possible, but I hope that someone does, soon.