Showing posts with label False Cause; Correlation Error. Show all posts
Showing posts with label False Cause; Correlation Error. Show all posts

Friday, April 25, 2014

The F-35 false dilemma

Ever since the announcement that the Australian Federal Government is going to buy 58 more F-35 Joint Strike Fighters at a cost of $12.4 billion, the anti-Government social media memes have been in full swing.
There’s nothing wrong with criticising any specific Government policy. The report linked to above outlines some of the (I assume legitimate) criticism of the JSF program. However, memes such as these are examples of disingenuous (I won’t say idiotic) and win-at-all-costs thinking that only serve to reinforce partisan politics and do not lead to civil discourse or help with getting to the truth of a matter. 
Specifically, these arguments make the false dilemma fallacy - the error of portraying one choice as necessarily excluding another, even though there is no necessary connection; and the false cause fallacy - asserting there is a causal link between the funding of the JSFs and other funding. 

Even if one doesn’t like a particular political party, organisation or person, every issue should be treated on its own merits and in good faith. To do otherwise is to engage in dogmatic unthinking. Politically, announcing the $12 billion spending adjacent to discussion of spending cuts in other areas might not have been very savvy. However, a disinterested analysis recognises that one has nothing to do with the other, anymore than any other government expenditure. 

The total 2013 budget for Australia is almost $400 billion. As this interactive shows, social security and welfare is $138 billion, education is nearly $30 billion, and recreation and culture is $3.7 billion. These figures are for a single year. 

My understanding is the $12 billion had been accounted for in the defense spending cycle. Unless you are a complete pacifist who believes Australia should disband its military (in which case I say good day to you sir/ma’am, could you please leave my website and go back to playing with your imaginary rainbow unicorn), you will recognise the need for this spending. You might disagree with this specific program, on its own merits, but not based on some supposed link to another completely unrelated program. 

Unless you can establish that Australia could spend, say, $3 billion less on alternative fighters that have similar capabilities; and that this $3 billion could go to another area of government expenditure, you are clearly interested in winning a political fight, rather than discussing a real issue.

Monday, October 01, 2012

False Cause; Correlation Error

Other Terms and/or Related Concepts

Post hoc ergo propter hoc (after this, therefore because of this); false association; superstitious belief.


This fallacy is the result of the common human tendency to associate events which occur in sequence and to assume that there is a causal link. When an advocate claims that there is a causal relationship between two events, they need to give a plausible reason beyond simple association. If the advocate cannot do this they are probably in error. There are two possible "levels" of false association:

  • The relationship may simply be apparent rather than real (e.g. coincidence). In this case the error is a false cause because there is no causal relationship.
  • There may be an actual link, but the direction of cause and effect claimed by the advocate is incorrect. In this case the fallacy is correlation error because the cause and effect are reversed, or indirectly related.


  1. False Cause: Trixie Trendy-Chump has just opened up her new business card business – The Business Card Business. One week after opening, her total sales amounts to one pack of fifty cards for the local gravel merchant. She is talking to her husband Bevan Chump-Trendy about how she can improve sales. "I was reading recently about how Beijing is going through an economic boom. Now, everyone in China practices Feng Shui. They don't even think about setting up a shop without consulting a Feng Shui guru to make sure the energy lines of the store are conducive to business."
    Bevan responds: "So what you're saying, is that Feng Shui has made Beijing money, so why not you? Sounds good to me!"
  2. Correlation Error: Aaron Fibreglass is writing up his report on the link between self-esteem and obesity. He concludes: "There was a correlation of 0.8 between morbid obesity and low self-esteem. We need to raise the self-esteem of obese people to help them overcome their weight problem."


In the first example Trixie and Bevan assume there is a causal link between Feng Shui and economic prosperity. However, if Beijing is undergoing economic growth and its citizens happen to practice Feng Shui, it does not follow that Feng Shui is the cause of the economic growth. This relationship may simply be apparent rather than real – that is, a coincidence. To establish whether or not Feng Shui can influence economic prosperity, systematic tests would need to be conducted.

In fact at any one time, a great many cities around the world are going through economic growth. Few, if any city administrators give any consideration to Feng Shui. There are no doubt a great many other cites in China where Feng Shui is practiced. What is their economic activity like? The seeker after truth should always ask questions which go beyond mere association, and look for alternative possibilities.

In the second example, Aaron claims low self-esteem causes obesity. However on the evidence presented, causation could be in the opposite direction – obesity could be the cause of low self-esteem. Or both could be caused by a third, unidentified variable. To a skeptical scientist, such a strong correlation between obesity and low self-esteem is potentially of great interest, but a series of sophisticated follow-up studies would be needed to determine the nature of the correlation and the direction of causation.

False cause can have very serious consequences. For example, the false cause fallacy during the European dark ages led to the widespread belief that illness, famine and personal misfortune was caused by black magic and sorcery. Such beliefs led to "witch-hunts" (literally) and unfounded but widely believed accusations of sorcery. The absence of skepticism in communities wallowing in superstition led to the burning to death of innocents falsely accused of witchcraft. This still happens in the present day in societies that lack good governance and are dominated by superstition.

The false cause fallacy varies in the magnitude of the problems it causes. From the simple and harmless superstitions of sports people undertaking rituals or wearing a "lucky charm" in order to perform well, to the harm caused to seriously ill people when diverted from effective treatments to ineffective or harmful treatments by quacks or frauds.

Wednesday, December 10, 2008

Podcast: Hunting Humbug 101 - Tutorial 10: False Cause; Correlation Error (feat. Jenny McCarthy)

In this podcast we discuss the False Cause; Correlation Error. It’s the 1st pod in a series we are doing on the air head actress Jenny McCarthy and her fallacious views on autism.

Here's the link to direct download: (35 mins & 16 mb) and you subscribe here: by clicking one of the buttons below.

The "cut down" video podcast version:

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Thursday, October 23, 2008

Astrology passes as news these days...

Earlier this week I posted about equity strategist John Wilson, who essentially said nothing useful about the plunging stock markets. Even though Wilson was tautological, at least he was not as inane as these morons:
From his base in India's financial capital Mumbai, Raj Kumar Sharma has been tracking the turbulence in the world stock markets and has come to one firm conclusion - it was written in the stars.

Where many blame banks overstretching themselves or inadequate financial controls and policy, Sharma sees a clash between fiery Saturn and its arch enemy Leo as a key factor in the recent financial turmoil...

"Leo is the sign of the sun and the sun is the father in Indian astrology," he said.

"But the son (Saturn) and his father (the sun) don't get along, so whenever they are sitting in the same house together, they always fight and create ill-will and danger in the market," he said...

"That's why Lehman Brothers fell," he said of the US investment bank....
His "colleague" Christopher Kevill:
"I don't think the planets 'cause' anything to happen on Earth - they are mere correlations based on some larger principle of interconnectedness," he explained.
They should really get together and try to get their stories straight. One claims causation and the other doesn’t? (If the planets don’t cause things to happen on the Earth, then… perhaps our actions on the Earth cause the planets to orbit!)

Kevill, the one who doesn’t claim causality, hasn’t confused Correlation with Causation, but of course, he should at least demonstrate there is correlation. I have my doubts... I’m equally as good at Postdiction as they are - predicting things after they’ve happened. And let’s not get into his unsubstantiated claim (read: non-existent made up BS) of a "larger principle of interconnectedness”.

Now as bad as these two arseclowns are – they don’t quite measure up to the pathetic “journalist” and editor(s) who published this drivel. Such a pointless piece in any newspaper or on the web (in the business section!), without any hint of skepticism, or what I would consider to be basics of journalism, like asking critical questions of the interviewee(s), is shameful.

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Hat Tip: Humbug reader Ben.
Source: Saturn, Leo to blame for global meltdown - Brisbane Times (Oct 17 2008)

Sunday, June 22, 2008

Not a week goes by...

until some some study comes along for a news source to confuse correlation with causation. I just wrote about emos and now it's mobile phones that are bad for teenagers:

...teens who made more than 15 phone calls and sent more than 15 text messages a day, slept poorly and had more careless lifestyles compared to those who made less than five of each per day.

Conducted by Sahlgren's Academy in Sweden using 21 teenagers...

Note it is only on 21 subjects. Not exactly a large sample size.

Now, as I said with my emo post, I wouldn't be surprised if it is the excessive use of the phone that is the cause of the lack of sleep. But, it could just as easily be the lack of sleep means they have nothing better to do than text their friends... You need to rule out this hypothesis before you know the direction of the cause. Otherwise you could be making the False Cause; Correlation Error. Perhaps the authors did this, but if so, the article does not make this clear.

What it does go on to say, after the quote above:
...the study found teenagers who made at least 15 calls and messages a day spent more time on computers and drank more caffeinated drinks and alcohol, had more irregular sleeping hours and found it more difficult to wake up and were more tired before midday.
And as you can see, we have uncontrolled variables. If we want to establish the mobile phone use as a causal mechanism for poor sleep, we'd need to rule out the other potential causes, e.g., the caffeine and booze. Perhaps they are addicted to caffeine (a drug) which keeps them up, which leads them to text and myspace, which keeps them mentally stimulated, which leads to more coffee or Red Bull, etc. A vicious circle or sorts, and another hypothesis.

To see the effect of the phone on its own, you'd need to control for these other variables. A simple experiment to set up. Perhaps the "natural" experiment has been done. Is there evidence of an increase in teen sleep deprivation (above and beyond better diagnoses) over the last 10-15 years?

Moreover, the article then goes on to relate this study to an unrelated one:
The second study, conducted by Fred Danner at the University of Kentucky on 882 Year 9 students, found teenagers who slept less than eight hours a night got worse grades and had a higher level of emotional disturbance and risk of ADHD.

The unstated claim is lack of sleep leads to worse grades. If this is the direction then I won't be surprised. But surely you have to get some students who were doing poorly to sleep more and see if their grades improve?

Note that by linking these two studies together, we now have the implication that using mobile phones leads to poor grades

I'll tell you what I would bet on. When questioned at length, I'd bet the authors of these studies would qualify these claims along the exact lines I have. The number one thing they'd say is more research needs to be done. In order to form any real position on claims in a field of current research it's best to take studies like this as interesting, but not conclusive. Wait and see where we are at in another ten years.

A problem with non-science journalists reporting science, is they don't often put qualifiers like this in the story. This can to lead to claims of Exaggerated Conflict from those wanting to dispute scientific claims. Think about climate science, or the reporting of stories on health and nutrition. Ben Goldacre writes about this very point in his Bad Science blog.

Sunday, June 01, 2008

Leave the emos alone

I don't know anything of this story other than this article:
Around 100 teenagers have marched on the offices of a widely read British tabloid to protest at its suggestion that their favourite emo band, My Chemical Romance, encouraged suicide.

They say they object to Daily Mail's description of the US group as a "suicide cult band" in an article about a teenage student who hanged herself two weeks after she started listening to its music...

...The article that sparked the protest concerned a coroner's inquest into the death of Hannah Bond, 13, who hanged herself allegedly after starting to listen to the band's music and becoming obsessed with death.
I have to say I agree with the emos#. The implication is listening to music can be a causal agent for behaviour (in this case, suicide). This is an old argument, previously applied to rock and roll, punk, hip-hop, heavy metal, techno, grunge and now emo. There may be a correlation with behaviour and music, but correlation does not demonstrate causation.

I'm not worried about the actual facts of this sad story, or even if the Daily Mail made the claims as reported. Assuming the above is all correct we have a common example of the post hoc error (post hoc ergo propter hoc - after this therefore because of this).

The classic example is violent TV shows/movies/video games (entertainment) are correlated with violent behaviour. Therefore, some claim, violent entertainment causes violent behaviour. On it's own, correlation does not mean causation, it merely shows two variables may be linked. As such, there is good reason to investigate further.

Until further investigation is conducted, correlation does not show which direction the link (if there is one) goes. It also does not rule out the hypothesis that a third factor could be the causal agent of change for the two correlated variables.

For example, perhaps naturally violent people are attracted to violent entertainment. I.e., there is causation, but in the other direction. Or, perhaps there are no "naturally" violent people, but the social group they happen to be in promotes violence (this is the third factor). As such they are prone to acting more violently and being entertained by violence.

This is not to say violent entertainment isn't the cause (or rather, one of the causes) of violent behaviour, just that you have to show more than a correlation to substantiate this claim. Something along the lines of controlled experiments with half the randomised subjects watching Bambi, the other half watching Rambo, then getting them to give each other different strength electric shocks (measure who is the most prone to increase the voltage) or some other twisted experiment psychologists seem to enjoy creating.

Cause and effect with human behaviour is generally not unidirectional. For whatever it's worth, my bet would be, whilst violent entertainment or suicidal music is not the cause of correlated behaviour (but rather an effect of predispositions) it may reinforce and increase behaviour in the manner of a positive feedback loop.

#Just because I agree with them in this case doesn't mean I have any real time for people who sit around pretending to be depressed.

Friday, June 15, 2007

Alzheimer's Survey Shock Finding

From "America's Favourite News Source - The Onion. For those critical of survey data... worth a look.

Saturday, January 06, 2007

UFO cause by global warming! WTF?

Initially, when I read the following:

Officials are mystified after a mysterious metallic object crashed through the roof of a New Jersey home, although one expert said it could be a meteorite…

The object is the size of a golf ball but weighs as much as a can of soup, according to AP.

"I saw it's a UFO," said one neighbour.

Another believed it was connected to "some kind of global warming thing."

I thought that the most appropriate fallacy would be False Cause; Correlation Error, as the second neighbour attributed the UFO (the first neighbour is right, at this time it is an Unidentified Falling Object) to global warming. However, the False Cause; Correlation Error requires the erroneous belief that there is a causal link between phenomena to be apparent. The only thing apparent in this case is that the claim that a UFO is caused by global warming is simply moronic. It puts the "M" in stupid. Hence my classification of the above claim as a WTF? Fallacy instead.
Via: Tim Blair

Source: Mysterious object crashes into New Jersey home - - 5 Jan 2007

Saturday, September 23, 2006

A and B are in “success”… if you misspell it

Andrew Robinson emails this example of dodgy reasoning:

I was at a conference last Friday, and two presenters made the following argument.

1) We note that certain projects are successful.

2) We examine the characteristics of successful projects, and we find A and B in common to all the successful projects.

3) Therefore A and B are desirable factors for projects.

Obviously, in failing to examine the unsuccessful projects, the reasoner misses the factors that are common and unique to all the successful projects. So, they fail to adequately distinguish the successful from the unsuccessful projects.

Does that fallacy have a label?

Talking to Jef, we agreed this is an example of the False Cause; Correlation Error (post hoc ergo propter hoc), as they haven't actually established a causal relationship between "A and B" and successful projects. To establish this they would need to alter "A and B" to see if there is any marked effect. If so, it would be reasonable to suppose that "A and B" are causal agents.

However, even if "A and B" are causal agents, the presenters are still guilty of Observational Selection; as pointed out by Andrew, they haven't looked to see if "A and B" were also characteristics of unsuccessful projects. (If they have looked, but ignored counter evidence, it would be Stacking the Deck.)

This opens up the deeper philosophical question; how can one establish a causal process? I’ll ramble on about causal processes in my next post.

Update - here's that post on causal processes.
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Email via Tim van Gelder

Tuesday, July 18, 2006

Shock findings - high achievement causes more homework

The poor man may have been misquoted - after all, the article was written by a mere journalist, but embedded in the following quote is (by implication) a classic False Cause fallacy (Post hoc?... ergo propter hoc?).

John Roulston, executive director of Independent Schools Queensland said a good rule of thumb was that homework should be assigned on the basis of 10 minutes for each grade level up until senior school.

Dr Roulston said homework at most independent schools ranged from 10 minutes a day for Year 1 students to 20 minutes a day for Year 3, 60 minutes a day for Years 6 and 7, 75 minutes for Year 8 and 90 minutes for Year 9. Year 12 students often did up to three hours home work a day, he said.

"Schools in which homework is routinely assigned and graded tend to have higher achieving students," Dr Roulston said. "The more homework students complete, especially from grades 6 to 12, the better they do in school. "The correlation between homework and higher achievement is higher the further a student moves through school."

Sounds reasonable but... higher aspiring students, with pushy parents, might do more homework - and achieve higher results - because of their pushy parents and higher aspirations. More homework might not "cause" higher achievement, despite the superficial attractiveness of such an assumption.

Maybe Doctorates in education cause executive directors of independent schools to jump to hasty conclusions - or to confuse correlation with causation? The only way to really test Roulston's assumption that more homework gives more betterer results in school would be to force slackers to do mountains of homework and to forbid keen students to do any. I shall be applying for a grant to conduct just such a study.

Tagged - , , .

Monday, June 26, 2006

Global warming causes my clothes to dry quicker

I've sent this amazing story to ABC News in the US.

Dear ABC News,

I've noticed over the last few years that when I hang my washing out to dry, it has started to dry quicker than it used to. I believe this is firm proof of global warming and it's effect on my "everyday life". I have written this preliminary note to point this out to you, but as requested, I'll make a video too. I've also noticed that I have to mow the lawn more frequently in the last few years - I've set up a time lapse camera to film this and I'll provide the footage shortly - more proof of global warming.

Regards, Theo Clark

Why would I send such an obvious load of rubbish to them you ask? Well, they asked for it:

Witnessing the impact of global warming in your life?

ABC News wants to hear from you. We're currently producing a report on the increasing changes in our physical environment, and are looking for interesting examples of people coping with the differences in their daily lives. Has your life been directly affected by global warming?

We want to hear and see your stories. Have you noticed changes in your own backyard or hometown? The differences can be large or small — altered blooming schedules, unusual animals that have arrived in your community, higher water levels encroaching on your property.

Show us what you've seen. You can include video material of the environmental change, or simply tell your story via webcam.

I guess one can't expect members of a news team to be able to understand such complex concepts as the False Cause; Correlation Error.

I am coping reasonably well by the way. The increased rate of grass growth (thus an increase in the frequency of lawn mowing) is annoying, but I do like the fact that my clothes dry quicker.

Update: David Icke points out in his comment that global warming is actually a fiendish plot by shape-shifting reptilians; groundwork for their immanent invasion of earth.

I have noticed an increase in Gecko numbers over the last few years… Perhaps this is a product of global warming too? Though I hadn't considered the possibility that this was an alien invasion from an extra dimension. I just assumed they were from China or something.

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(Via Tim Blair)

Saturday, April 01, 2006

Crap TV makes make oldies stupid

Who’d ‘a’ thunk it? (Me dis afanoon wach Jerry Springer, Oprah, and da Bol an da Beauful. dam it... wat me rite nex... ummm me brane urt... got me hed stuk in da cupbord... neeed momont too figre owt...)

Soaps, Talk Shows May Dull Aging Brains:

New research suggests that elderly women who watch daytime soap operas and talk shows are more likely to suffer from cognitive impairment than women who abstain from such fare.

[1 hour later - slaps self in face] I’m okay now.

Back to the point. It could be that watching garbage on TV makes elderly women stupid, or, of course, stupid elderly women may be attracted to watching crap shows, as they are too stupid to enjoy anything else. Or it could just be a coincidence.

To conclude that it’s the TV shows which are causing lower cognitive ability is a classic case of Confusing Correlation with Causation. To be fair, the article I’ve examined, doesn't end up doing that; it goes on to cite the researchers’ emphasis that they do not propose a hypothesis as to what causes what:

Researchers stress that it's not clear if watching these TV shows leads to weaker brainpower, or vice-versa. And they say it's possible that another explanation might be at work... Their findings appear in the March issue of the Southern Medical Journal.

If I were a gambling man I’d guess it’s a bit of both. Stupid to start with and you then become stupider the more you watch. (I’ll "justify" this position with Flawed Circular Reasoning. You’d have to be stupid to watch it in the first place, as only stupid people would watch it. And you get stupider as you watch it, as you’d have to be more and more stupid to continue to do so.)

Note - Obviously (I hope!) I am not implying I'm and elderly woman (not that there's anything wrong with being and elderly woman) at the beginning of the post where I pretend [deliberate emphasis] to be stupid. (And apologies to Monty Python.)

Thursday, March 23, 2006

Faculty Follies - Correlation is Not Always Causation

A study reported in the Higher Education section of The Australian on March 22nd is alleged to have found that "just turning up gives female students an edge over the men". However what was actually established by the study was that "attendance has emerged as the best predictor of academic performance".

The authors of the study are claiming insights which are not supported by their research. Attendance may be a good predictor of academic performance, but that does not mean that attendance is also a cause of better academic performance. High levels of attendance and high levels of performance may both be caused by another variable... perhaps high achievement motivation. The false cause/correlation error is easy to miss when prediction is confused with causation.

Thursday, February 02, 2006

Coffee Causes False Cause; Correlation Error To Be Acceptable

I teach a course on alcohol and drugs at Walladumpdung University (I use the fake name Walladumpdung so that no-one knows that I actually teach at Griffith University). I don't drink alcohol, I don't smoke, and I don't use illegal drugs or abuse pharmaceuticals; so I don't experience a crisis of conscience when I expound on drug and alcohol issues.

However I do drink coffee. I LOVE coffee. So naturally when I look at drug and alcohol research on coffee I make sure I only pay attention to literature which shows that coffee is either harmless or good for you. If for example, a study finds that people who drink lots of coffee are less prone to dementia, I will assume, as do the researchers, that coffee consumption is protective against the onset of dementia. Of course, both I and the coffee-loving researchers know that the causal relationship could be the other way around - that is, people who are not naturally prone to dementia are more likely to like coffee.

But hey, if you're looking for an excuse to drink coffee, the occasional False Cause; Correlation Error can be safely ignored.

Um... on a personal note... if anyone knows of a study which shows that weight gain causes excessive food intake I would be interested in following it up.