Sunday e-mail 26th May: Numbers, killers, & killer numbers
What excitement to expect this week; a serial-killer bullet list
Let me tell you something you may find surprising. Statistics are interesting. Go on. Give me a chance. Have I ever led you astray?
Numbers… Scientists have always been big fans. They were big fans even before the word scientist was invented. But statistics, they’re something different. When they appeared in the nineteenth century, they immediately changed what the scientists did for a living.
Two questions spring from that: Why and how? Why did statistics come along so late in history? What effect did they have?
Why so late? In a word, free will. Only by the nineteenth century do we see religion’s grip on western science loosen. Eternal reward; eternal punishment; heaven, hell - you know the sort of thing. For most, free will was implicated, that ‘great and terrible gift’ you’ve heard about.
Scientists were impressed by the success of Newton’s implacable equations in Physics. They seemed to indicate that the universe was governed by iron Laws.
This was a big problem for the actual law, the legal one. It was built on the idea of free will. Credit a school of thought called Classical Criminology, upon which many legal systems even in today’s postmodern world are still constructed.
The tension between free will and what scientists were calling determinism is one that still bothers psychologists and lawyers so much none of us ever mention it except after a few cognacs.
Onto our second question. Scientists were suddenly able to perceive regularities in the universe they’d never suspected before. The criminologist, Enrico Ferri, for instance, figured out that if you knew the French crime rate in a particular year, you could also figure out how the weather had been. Lambert-Adolphe-Jacques Quételet discovered that 2200 men had recently evaded the military draft by lying about their height.
This was amazing stuff. It looked like what it was – the door to a whole kingdom of knowledge. I want to tell you all about it this week in Crime & Psychology. Be here Wednesday for a tantalising trip into the world of numbers: digital prestidigitation if you will. In what way did statistics influence criminology and why? Who was responsible? And can you really measure human behaviour anyway? All these questions and more will be answered! All the cool kids will be there. Don’t miss it!
Serial murder. Statistics show me that’s the most popular topic on the whole Crime & Psychology Substack. So this week’s brilliant bullet-list features five stunningly statistical, niftily numerical, facts about that very topic. Let’s go:
1. Offender profiling was developed in the 1970s in response to the perceived increased in serial crime in the United States. As anyone knows who has seen Mindhunter, it was developed by a group of ‘rogue FBI agents’, who, not satisfied even with having the words ‘rogue FBI agent’ on their curricula vitae (is there no pleasing some people?), interviewed a group of convicted sexual murderers on Death Row. That’s how they first developed their profiling tools. The surprisingly small number of interviewees: 36.
2. Percentage of cases in the UK (around the turn of the century) in which offender profiling actually led to identification of an actual criminal: 2.7.
3. Probability of being the victim of serial murder if you live in the United States: certainly less than 1 in 100 000, and likely as low as 0.2 in 100 000. That’s almost vanishingly small. The probability of being a victim in the UK, on the other hand, may be up to ten times greater. Google it in the UK and you learn this: ‘You're statistically 470 times more likely to be killed by a serial killer than you are to win the national lottery jackpot’. I can’t personally swear to the truth of that, since I haven’t done the calculations, but it can’t hurt to take a bit of care, can it?
4. Number of serial killers active in at any one time: Well, as you can imagine, it’s tricky to put a number on this. There is going to be a substantial dark figure (what Donald Rumsfeld might call a ‘known unknown’). That doesn’t prevent some criminologists from trying. The best American estimate put it around 35 at any one time throughout the 1970s and 80s. It’s probably a little higher now. I’ve seen some put the number in nosebleed-inducing triple digits, but you have to wonder whether certain criminologists just fancy seeing their names in the news. In the United Kingdom, put the number down into single digits.
5. Number of victims required to be classified as a serial killer: Just 3, despite attempts to raise the bar in recent years, owing to the fact that too many people were, so to speak, qualifying. More important than the raw number, though, is the gap that must occur between the killings – a kind of ‘cooling off’ period. If a person kills three victims at one time, that’s mass murder, not serial killing.
Thank you for your thoughtful comments! I’m planning a newsletter on the state of the game in offenders profiling. I hope it will be out in a month or so. Stay tuned!
No apology necessary, Karl! It’s good to chat about these topics. Apologies for my late reply, by the way. I was away for a few days and just came back.
Is the ‘Sexual Homicide’ book you mention the one by Burgess & Ressler (I think they were the authors)? That’s the FBI’s first attempt at classifying serial killers. It introduced the works to the distinction between ‘organised’ and ‘disorganised’ killers. That one is still around, but the most recent meta-analysis I’ve found in the litter actually indicates that various papers over the last decade or so have changed and added to the typology endlessly. It’s a developing field and who can tell what’s going to come along next?
Depending on how you classify serial killers, then, there are digests if deciding whether they are sexually-motivated. In fact, some writers have claimed that all serial killers are ultimately sexually motivated. Others think power or a sense of mission is more important in explaining some categories of serial killer. It’s all change and it’s be a brave psychologist who made a prediction about what the next classification is going to be.
Anyway, when they say profiles were ‘helpful’ it’s not necessarily the case that they have any scientific definition of the term in mind. In fact, early work in serial killers was notoriously unscientific in nature. It’s perfectly possible they just meant a police off over hit in touch and said, ‘Thanks, that was helpful’. For sure, the FBI has been quite invested in making offender profiling appear impressive. You never read a book by an FBI profiler in which they tell you modestly about all their failures. That’s a problem in itself of course and tends to add yet another layer of uncertainty…