How smart was Sherlock Holmes's arch enemy Moriarty?

Statistician Garth Zietsman asks how intelligent someone would need to be to become a real world Moriarty, a criminal mastermind who consistently escapes justice. Using Bell Curve data and US serial killer statistics, he estimates that evading a single murder charge takes roughly the cognitive ability needed to finish junior college, while getting away with three murders is somewhat harder than earning a basic degree. He puts the number of genuinely genius-level killers in the US at around a dozen. Locally, the piece notes South Africa's murder clearance rate is just 11.3 percent against America's 62 percent, suggesting the intelligence bar for escaping justice here may be considerably lower..By Garth Zietsman*.Let’s face it – to the law-abiding, crime usually seems stupid. The low average IQ (92) of men in US jails supports that impression.Those jailed for violent crime are even less endowed intellectually – IQ 84. Why is that? Is it because the unintelligent are simply more likely to commit serious crime because they are stupid? That is part of the explanation, but it isn’t all of it.For a start, a fairly large fraction of crime goes unpunished. The national clearance rate for murder in the US was only 62% in 2011. For lesser crimes it’s much lower.Furthermore, the clearance rate has been dropping for some time, in spite of better law-enforcement technology. Part of the reason is rapid urbanisation. In small rural areas, where everyone knows everyone, it’s hard to avoid detection, but in large urban areas it’s easy to stay anonymous.Given that so many people are getting away with serious crime, does high intelligence increase the chances? (The murder clearance rate in South Africa is only 11.3%. I will leave the inference about our police ‘service’ to the reader.)There is some data. Charles Murray and Richard Herrnstein’s The Bell Curve shows a graph of the probability of being in the top 10% of self-reported crime, by IQ (with the effect of social class controlled.)It slopes slightly upward with increasing IQ. Another line sloping downwards shows the probability of having a criminal record by IQ. So, brighter men are both more likely to be in the top 10% of self-reported crime, and less likely to have a criminal record.Research has ruled out systematic bias in the prosecution process, so differences in getting away with crime must be due to avoiding detection.Clearly brighter men do less jail time per unit of crime – that is, they are more likely to avoid detection or identification. That shouldn’t be a surprise.Performance on any task requiring thought is mostly explicable by a single general cognitive factor, measured most reliably by IQ tests. Committing a crime involves overcoming barriers and without leaving evidence that could aid the police. That definitely requires problem-solving and foresight. Success in any endeavour, including evil, favours the more able.Wouldn’t it be interesting to know your chances of being a successful Evil Genius? I mean, just how hard can it be to be another Professor Moriarty?SpeculationTo get an idea I had a go at putting numbers to this speculation. I combined the two Bell Curve graphs to produce a curve showing the probability of not doing jail time, given that a man was in the top 10% of self-reported crime. While this is interesting, it’s more interesting to show the probability of getting away with a serious crime like murder, because then one will be up against the best efforts of the police. At the end of the day, it is a macabre chess game.Not many people admit to murder in self-report crime surveys, so I had to think of another way to estimate the odds of getting away with murder by IQ. My approach involved serial killers in the US, and some creative statistics. I used the technique called logistic regression and added some calibration tweaks. You can see the results in the graph below.To give some perspective I also include curves showing the probability of finishing high school, junior college, college and graduate school in the US by IQ.As you can see, getting away with a single murder in the US is much like school or junior college in its intellectual demands – just shy of junior college in difficulty. Avoiding jail time for top 10% levels of self-reported minor crime shows a similar pattern but is closer to high school in difficulty.Even serious crime doesn’t look especially demanding intellectually. Becoming a successful serial killer – getting away with three separate murders – is slightly tougher than a basic college degree, but still a lot easier than obtaining a post-graduate or professional degree..To be fair, getting away with murder would be more cognitively demanding if the police were brighter.As it is, they occupy a very limited range of ability (average IQ 104 and maximum IQ 110.) Human resources told one applicant above the upper limit that boredom was a risk for him and that he might cause friction with less intelligent policemen.On the other hand, during the Great Depression the New York police hired a group of men strictly from the top of the list of test scores. These men proved to be extremely effective policemen. They solved way more cases and most ended up in very senior positions.The FBI are smarter (IQ 115-120+) than standard policemen, but they don’t work on every murder. They do however work on serial killer cases once the various police agencies connect the cases. Serial killers eventually ‘play’ their chess against a team within the 85th to 95th percentiles of ability. Not exactly grandmasters but almost as bright as professionals like doctors, lawyers and engineers. That may explain why attaining serial-killer status looks more difficult than committing a single murder.I suggest two ways to define the minimum requirements for a Moriarty level IQ.a) The same as other geniuses, Nobel laureates say, which is an IQ of 146 on average.b) Setting the minimum IQ at the level where the chance of getting away with murder is 95% or better. That implies an IQ of 152. The reason is that if a random process has less than a 5% chance of producing the effect we see, science accepts it as a true effect.Convenient compromiseA convenient compromise would be an IQ of 148, which falls neatly at the 1-in-1,000 level above average.I combined the likelihood of someone with a 148+ IQ actually murdering someone in their lifetime (1 in 8,217 men) with the probability of escaping justice (95%) and the rarity of that IQ (1 in 1,000.) I estimate that there were only around 12 male (and 1 female) genius-level killers in the US of 2011..Read more:.How SAPS killed its detective service - and let crime run wild: Fanie Bouwer.I used murder as a proxy for all equally serious crimes, so the numbers of evil geniuses are higher than that (a multiple of the number of equally serious crimes you can think of.)Nonetheless, the Moriartys of the world are mercifully much rarer than law-abiding geniuses like Sherlock Holmes. Unfortunately, almost nobody that smart works for law enforcement. Presumably because we don’t value catching killers as much as anything else we need those geniuses to do..*Garth Zietsman is a professional statistician who initially focused on psychological and social research at the Human Sciences Research Council, followed by banking and economics, and then medical research. Some of his research has appeared in academic journals. He has wide interests, with an emphasis on the social (including economics and politics) and life (mostly evolution, health and fitness) sciences, and philosophy. He has been involved with groups advocating liberty since 1990 and is currently consulting to the Freedom Foundation. He has written for a wide range of newspapers and journals..This article was first published by Daily Friend and is republished with permission..Sign up for your early morning brew of the BizNews Insider to keep you up to speed with the content that matters. Register here.Support South Africa’s bastion of independent journalism, offering balanced insights on investments, business, and the political economy, by joining BizNews Premium. Register here.If you prefer WhatsApp for updates, sign up to the BizNews channel here.

How smart was Sherlock Holmes's arch enemy Moriarty?

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