Mention just about any scientific finding involving a chain of causation — anthropocentric global warming, monarch butterflies/milkweed destruction, fluoridation/fewer cavities (“Colorado Brown Stain,” May 31) — and you’ll hear “correlation isn’t causation” from skeptics. And they’re right. If you suggest A causes B, they’re going to ask, “How are you so sure B doesn’t cause A?” (Does high self-esteem cause kids to get high grades or the other way around?) Or, “How do you know C doesn’t cause both A and B?” (Does the correlation between increased ice cream sales and more drownings mean that ice cream causes drownings, or does hot weather cause an increase in both?) In fact, it’s often impossible to prove that A causes B with 100 percent certainty.
Solid Correlation-causation: Smoking and lung cancer. The poster child for causation is smoking and lung cancer. We all know that smoking is the prime cause of lung cancer. Except “all” doesn’t include tobacco company lawyers, who regularly point out that (1) fewer than 10 percent of lifelong smokers will get lung cancer and (2) non-smokers also get the disease. (This probably won’t convince anyone to quit so if I were a doctor, I’d turn the statistics around and tell my patients: Smoking accounts for 30 percent of all cancer deaths and 87 percent of lung cancer deaths; male smokers have 23 times the risk of developing lung cancer as non-smokers and life expectancy for tobacco smokers is 14 years less than the national average.)
How can we be sure that smoking causes lung cancer? We can’t and it doesn’t — not definitively. It adds to the risk, sufficiently for most of us to either quit or never start. Evidence for the increased-risk causation is solid, starting with statistical studies in the 1950s, when the American Cancer Society followed the smoking habits of 188,000 men; the ones who died of lung cancer were much more likely to have been smokers than not. Also, researchers can actually see that smoke damages epithelial cells lining the windpipe and lungs, reducing the ability of the hair-like cilia on the surface of these cells to push mucus out of the lungs (hence smoker’s cough). Not to mention the several dozen carcinogenic chemicals found in tobacco smoke. And on and on.
Shaky Correlation-causation: Breakfast and obesity. WebMD is a reputable healthcare website. It’s the first place many of us go when we have an odd pain or weird swelling or dizzy spell. A few years ago, WebMD published an article under the heading “Eating Breakfast May Beat Teen Obesity.” The article summarized a study published in Pediatrics which analyzed the five-year diet and weight patterns of over 2,200 adolescents in Minneapolis-St. Paul, Minnesota. According to the WebMD summary, “Teens who regularly ate breakfast tended to gain less weight … than breakfast skippers” and “regular breakfast eaters seemed more physically active than breakfast skippers.”
So the article suggests that A (eating breakfast) causes B (more activity). But maybe B causes A: physical activity makes for hungry kids. Or maybe C causes both A and B, where C is physical activity which leads to both hunger for breakfast and calorie burning, which helps reduce obesity. Or (from a suggestion by science educator Sal Khan, from whom I first heard about this study) perhaps the root cause (C) of both skipping breakfast and obesity is poverty, that is, poverty results in both parents leaving the house early for work, so the kids don’t get proper breakfasts and they’re eating less healthily, leading to obesity. Now eating breakfast may indeed help alleviate obesity in teens. But the study as reported sure didn’t make the case for causation.
To sum up: Correlation is “When A happens, B happens, and vice versa” while causality is “A causes B.” Time to ask yourself: Does reading the Journal make you happy or does feeling happy make you read the Journal?
Barry Evans (barryevans9@yahoo.com) can’t decide whether he’s alive because his heart beats or his heart beats because he’s alive.
Related Stories
This article appears in ‘Highway Robbery’.
This article describes a critically important concept (Correlation noes not necessarily = Causation) which helps explain why anti-science activists (fluoridation and vaccination opponents, UFO and chemtrail believers, global warming deniers, et cetera ad nauseum) are often able to scam well-meaning citizens, create apparent scientific controversy where there is none and sway public opinion to disbelieve and reject legitimate scientific conclusions.
The only solution to this dilemma is to trust the established scientific consensus of relevant experts on specific issues — or become a qualified expert yourself.
Cause and effect is one of the most commonly misunderstood concepts in science and is often misused by lawyers, the media, politicians, [activists] and even scientists themselves, in an attempt to add legitimacy to research. Unfortunately, most of the general public are not scientists and cannot be expected to filter every single news item that they read for quality or delve into which group funded research. Even respected and trusted newspapers, journals and internet resources can fall into the causality trap, so marketing groups can influence perceptions. (Martyn Shuttleworth)
https://explorable.com/cause-and-effect
Although the goal of science is to use controlled observations and experiments to determine as clearly and accurately as possible specific cause and effect relationships (causality) in nature, as Barry explained, it is often extremely difficult to distinguish the actual causes for a specific effect/phenomena from events which may only be related in time (correlated) to the outcome of interest.
Another goal of nearly all scientists is to use the knowledge of how nature works to adjust nature in various ways (in healthcare, engineering, agriculture, etc.) to improve the condition of mankind.
Unfortunately, any complex scientific/health issue with decades of research will have “mixed” results when scientists try to establish causality. The difficulty of establishing an exact cause in many instances, in addition to the potential of poor quality study design/execution/analysis, failing to identify other issues which might impact an experiment/observation (confounding factors), and personal biases can all influence the published outcomes.
Also, for any complex proposed cause and effect relationship (for example – potential causes of, or reduction in, tooth decay or cases of flu or autism), there are perhaps dozens of possible interrelated causes and numerous other phenomena which may only be correlated with the effect of interest.
~> Search on, correlation does not imply causation for example, to see how it can be proven that autism can be caused by eating organic food.
All these factors which can influence research quality and conclusions are precisely why the scientific consensus of experts who are qualified to understand and evaluate all of the available evidence is critical. Establishing a consensus separates the wheat from the chaff. Not all scientific studies are good quality, but by definition, any accurately performed study can be replicated by any other researchers(s). Over time the experiments/observations which are reliable and the conclusions that are accurate and trustworthy will become more obvious and validated by others. The most accurate, verifiable interpretation of cause and effect relationships will become the consensus.
Scientific understanding is constantly evolving the constant possibility of change in scientific consensus based on new, legitimate, verifiable scientific research is one of the most unique and important characteristics of science. Without a process that allows for a change in consensus, science would be an unchanging, authoritarian belief system, and all of the characteristics of modern society which are based on an evolving understanding of the natural world would not exist.
There will always be a relatively few outlier scientists who do not accept the scientific consensus and who must carefully pick and choose the “evidence” they accept. There will also always be non-scientists who have passionate beliefs and choose to believe the unsupported opinions of outliers over the interpretation of the actual evidence by the overwhelming majority of experts.
These anti-science activists (ASAs) are masters at establishing possible correlations which they proudly claim are proof of causes. ASAs who do not accept the scientific consensus also sift through the studies and pull out the chaff which they promote as legitimate, compelling research. The use of conclusions from mainstream studies and reviews distorted and taken out of context are a tactic also used frequently by ASAs.
The fact is that any scientific consensus will change if sufficient, legitimate, reproducible evidence is presented. The outlier ASAs have been trying to come up with legitimate evidence for decades without success that fluoridation and vaccination are harmful or ineffective that UFOs and chemtrails exist and the climate is stable. Consequently, the consensus has not changed and virtually all national and international health and/or science organizations and their members continue to recognize the benefits of both fluoridation and vaccination, believe climate change is a critical danger for most scientists and understand UFOs and chemtrails to be imaginary constructs.
Fear is often a far more effective motivator of beliefs than a considered evaluation of evidence particularly when the details are complex and the risks and benefits of peoples health is at stake.
Anti-health ASAs exploit the complexity of science and the power of fear to drive their anti-science, fear-mongering campaigns. ASAs will try and convince concerned citizens (most of whom have no relevant training or experience in evaluating complex scientific studies), that beneficial public health measures (vaccination and fluoridation) are actually evil incarnate. A primary argument used is that representatives of all supporting science/health organizations are either too stupid or incompetent to understand and recognize what the ASAs claim are obvious dangers of vaccination/fluoridation or all these professionals actually understand the issue but simply dont care about the alleged havoc these health measures are causing to the health of their families and fellow citizens. If those claims are even remotely true, everyone would have a lot more than these public health programs to worry about. In fact, virtually all national and international science and health organizations recognize vaccination and fluoridation as safe and effective public health measures and none recognize the opinions of ASAs
All alleged evidence presented by ASAs, used in their attempts to influence public opinions, has been carefully evaluated and dismissed by mainstream scientific & health communities. When ASAs present this evidence to the public it will have one or more of the following characteristics: 1) The study will have nothing to do with the subject; 2) Actual conclusions of studies have been deliberately distorted/misused/misstated to fit ASAs; 3) Conclusions will only be suggestion of a possible correlation without proper adjustment for other potential causes, and they are proof of nothing; 4) The study will be unrepeatable; 5) the study will be demonstrably flawed &/or 6) The claim will be a complete fabrication.
Bottom line: What makes more sense when trying to understand complex scientific subjects with decades of scientific evidence and thousands of studies?
1) Believe the scientific consensus the conclusions of the majority of relevant health experts and/or scientists.
2) Believe claims from vocal groups of ASAs who represent a small fraction of a percent of health and science professionals and employ unsupportable, often fear-laced propaganda to scare the caring citizens into opposing safe and effective public health measures, dismissing a potentially catastrophic climate change or accepting other anti-science fabrications as valid.
Search on safety and effectiveness of vaccination
~> https://www.parents.com/health/vaccines/controversy/vaccines-the-reality-behind-the-debate/
~> https://www.healthychildren.org/English/safety-prevention/immunizations/Pages/Vaccine-Studies-Examine-the-Evidence.aspx
Search on safety and effectiveness of fluoridation
~> http://who.int/oral_health/publications/2016_fluoride_oral_health.pdf
~> https://openparachute.wordpress.com/fluoridation/
Search on climate change deniers
~> https://en.wikipedia.org/wiki/Climate_change_denial
~> https://www.skepticalscience.com/argument.php
It’s all an idiom for debate, really. Who’s pushing what and why? Randy Johnson labels certain people “anti-health” and “anti-science” despite the clearly mutual intenion of being healthy based on science. Fluoride is a neurotoxic poison. Almost half the children in this country show physical signs of over fluoridatuon. Randy Johnson and Barry Evans would put chemicals in my body against my will. I would never do such a thing, nor even suggest it. If a person wants to eat toothpaste sandwiches, that’s their business, and their choice. Time to ask yourself, what’s your motive?
Art Spelling — What would your response be to anti-science activists (ASAs) who demanded that drinking water disinfection and other water treatment processes (pH adjustment, corrosion control, and coagulation/flocculation) should be halted because they “put chemicals in [their] body against [their] will”. Disinfection adds chlorine gas (used as a chemical weapon) or sodium hypochlorite (bleach) to the water.
All water treatment processes involve adding chemicals which are toxic at high exposure levels to water to protect and improve the health of citizens who drink the water. Decades of scientific research and experience have proven that the benefits of all water treatment processes to citizens far outweigh any risks. If you or others have severe paranoia against fluorine, chlorine, disinfection byproducts or other chemicals in treated water you are free to take measures to remove them or find your water elsewhere.
It is remarkable that you would choose to fight for a cause that is not supported by science and, if successful, would increase the risk of dental decay and related health issues in communities where ASAs prevailed.
You addressed none of the comments I made about the reason the scientific consensus is critical for understanding complex scientific issues. If you completely dismiss and ignore the consensus of relevant experts in topics like fluoridation and vaccination, what process you use to determine whether a specific belief based on science is to be trusted? Do you simply accept only what you want to believe and ignore everything else?
If there were any legitimate scientific evidence that supported the ASAs claims, explain why these activists have been unable to change the scientific consensus. Scientists and health professionals require legitimate, verifiable evidence to change their conclusions, not the paranoid opinions of ASAs. If you have legitimate evidence you believe proves drinking optimally fluoridated water causes (or has caused) harm to anyone provide specific citations and author quotes in context.
If the anti-F ASAs had any legitimate supporting evidence, explain why over 100 national and international science and health organizations (and their thousands of members) continue to recognize the benefits of fluoridation, why there are no recognized science/health organizations that recognize the anti-F opinions as legitimate, and why fluoridation opponents must distort the evidence to try and scare and scam the public into believing their propaganda is true.
~> http://ilikemyteeth.org/fluoridation/why-fluoride/
~> http://ada.org/en/public-programs/advocating-for-the-public/fluoride-and-fluoridation/fluoridation-facts/fluoridation-facts-compendium
Similarly, all major science and health organizations recognize the benefits of vaccination and no such organizations support the anti-Vax paranoia.
Time to ask yourself, what’s your motive for being one of the ASAs?
I grew up unfluoridated and live in Mckinleyville where the water isn’t fluoridated. I haven’t used fluoride toothpaste in over a decade. You want to put chemicals in my body against my will despite countless alternatives. I refuse to encourage a society that forces chemicals on people, especially in spite of countless alternatives. Barry Evans chooses to spend his time telling people to educate themselves on ingesting poisons rather than, say, educating people on countless alternatives, including very basic dental care. Fluoride is a neurotoxic poison and only a fool would encourage ingesting any amount of it.
Art Spelling — So, you continue to advocate for an increased risk of dental decay in communities without providing any proof that drinking optimally fluoridated water is either ineffective or harmful and without explaining how, if your opinions are even remotely true, the overwhelming majority of science and health professionals (and the organizations they represent) continue to accept fluoridation as a safe and effective public health measure like other water treatment methods, vaccination, etc.
Are you actually claiming that everyone in the world who supports fluoridation and has science/health training and experience is a fool? Why are there no nationally or internationally recognized science or health organizations that support the anti-F paranoia?
There are, indeed, a number of factors that can increase or decrease the risk of dental decay, and fluoridation of drinking water is one of them. Only a fool would demand that an effective and safe method for lowering the risk of dental decay and related health issues should be abandoned. Do you enjoy the prospect of more children and adults sitting under a dentists drill?
You havent even explained exactly how fluoridation will “put chemicals in [your] body against [your] will” — or how fluoridation will “encourage a society that forces chemicals on people”. As noted in my previous comment, anyone with a severe paranoia against fluoride ions (or those who would like chlorine, disinfection byproducts or other chemicals removed from their water) are completely free to treat their own water or find other sources.
Your comment, “Fluoride is a neurotoxic poison” without adding a critical qualifier, “at excessive levels of exposure”, is a common argument of fluoridation opponents, and it demonstrates a complete misunderstanding of the topic. Any substance you care to name — even water — is a toxin at excessive levels of exposure. Provide verifiable proof (specific citations and author quotes) that optimally fluoridated water is a neurotoxin. If there were such evidence the scientific consensus would change — the consensus of safety and effectiveness has not changed in over 70 years.
The only way fluoridation opponents (FOs) can make their claims denying the safety and effectiveness of community water fluoridation is because they completely ignore the 70+ years of research that supports the practice. Here are just a few recent studies and reviews the FOs have deliberately missed.
~> The 2018 National Toxicity Program study, An Evaluation of Neurotoxicity Following Fluoride Exposure from Gestational Through Adult Ages in Long-Evans Hooded Rats:
“At these exposure levels [0, 10, or 20 ppm F], we observed no exposure-related differences in motor, sensory, or learning and memory performance on running wheel, open-field activity, light/dark place preference, elevated plus maze, pre-pulse startle inhibition, passive avoidance, hot-plate latency, Morris water maze acquisition, probe test, reversal learning, and Y-maze. Serum triiodothyronine (T3), thyroxine (T4), and thyroid stimulating hormone (TSH) levels were not altered as a function of 10 or 20 ppm F in the drinking water. No exposure-related pathology was observed in the heart, liver, kidney, testes, seminal vesicles, or epididymides”
~> Water Fluoridation and Dental Caries in U.S. Children and Adolescents, (Slade, et al., Journal of Dental Research, 6/14/2018)
“These findings confirm a substantial caries-preventive benefit of CWF for U.S. children and that the benefit is most pronounced in primary teeth.”
~> The 2018 Water Fluoridation: Health Monitoring Report for England:
> “Five-year-olds in areas with water fluoridation schemes were much less likely to experience tooth decay, and less likely to experience more severe decay than in areas without schemes. “
> “The chances of having a tooth/teeth removed in hospital because of decay were also much lower in areas with water fluoridation schemes.”
> “Children from both affluent and deprived areas benefitted from fluoridation, but children from relatively deprived areas benefitted the most.”
~> The 2018 Food Safety Authority of Ireland Fluoride Report:
The study concludes that, based on scientific evidence, there is no safety concern for children and adults living in Ireland from exposure to fluoride through intake of foods and beverages.
~> The 2016 World Health Organization report: Fluoride and Oral Health:
> “More recently, systematic reviews summarizing these extensive databases have conrmed that water uoridation substantially reduces the prevalence and incidence of dental caries in primary and permanent teeth. Although percent caries reductions recorded have been slightly lower in 59 post-1990 studies compared with the pre-1990 studies, the reductions are still substantial.”
> “The question of possible adverse general health effects caused by exposure to uorides taken in optimal concentrations throughout life has been the object of thorough medical investigations which have failed to show any impairment of general health.”
~> The 2017 Swedish report, Effects of Fluoride in the Drinking Water:
“Taking all together, we investigate and confirm the long-established positive relationship between fluoride and dental health. Second, we find precisely estimated zero-effects on cognitive ability, non-cognitive ability and math test scores for fluoride levels in Swedish drinking water.”
~> The 2016 Australias National Health and Medical Research Council Fluoridation Report:
“The evidence shows that water fluoridation helps to reduce tooth decay in children and adults. There is no reliable evidence that water fluoridation at current Australian levels causes health problems.”
~> The 2014 Royal Society of New Zealand, Health effects of water fluoridation: A review of the scientific evidence:
“A large number of studies and systematic reviews have concluded that water fluoridation is an effective preventive measure against tooth decay that reaches all segments of the population, and is particularly beneficial to those most in need of improved oral health. Extensive analyses of potential adverse effects have not found evidence that the levels of fluoride used for community water fluoridation schemes contribute any increased risk to public health, though there is a narrow range between optimal dental health effectiveness and a risk of mild dental fluorosis.”
Smells like a fluoride troll. “Randy Johnson” would put chemicals in my body against my will, even despite countless alternatives.
Art Spelling — You sound exactly like base Commander Jack D. Ripper — with as much credibility: “I can no longer sit back and allow Communist infiltration, Communist indoctrination, Communist subversion, and the international Communist conspiracy to sap and impurify all of our precious bodily fluids.” “Do you realize that in addition to fluoridating water, why, there are studies underway to fluoridate salt, flour, fruit juices, soup, sugar, milk, ice cream? Ice cream, Mandrake? Children’s ice cream!…You know when fluoridation began?…1946. 1946, Mandrake. How does that coincide with your post-war Commie conspiracy, huh? It’s incredibly obvious, isn’t it? A foreign substance is introduced into our precious bodily fluids without the knowledge of the individual, and certainly without any choice.”
So, you are claiming that I would assault you and use some form of coercion (physical force or mind control, perhaps) to contaminate your precious body fluids against your will? Wow!!
All I am doing is stating facts that the overwhelming body of scientific evidence demonstrates that community water fluoridation is one of the safe and effective methods for reducing dental decay and related health issues. No one is claiming fluoridation is the only method to reduce dental decay, but it is an effective way to help protect the dental health of citizens.
If you are unable to personally avoid drinking water which contains any chemicals you have chosen not to ingest, or if you are unwilling to treat the water you drink to remove those chemicals, you have only yourself to blame. No one is forcing you to drink the water or contaminating your precious bodily fluids except yourself.
However, trying to halt an effective public health measure because of your inability to understand science is absurd.
You have not described how you would respond to someone who demanded drinking water disinfection and all other treatment processes be discontinued because they did not want to put chlorine, disinfection byproducts, or any of the other water treatment “chemicals in [their] body against [their] will.” You are not alone in your paranoia. In 1991, Greenpeace activist Christine Houghton said: “Since its creation, chlorine has been a chemical catastrophe. It is either chlorine or us”, and Greenpeace’s Joe Thornton stated, “There are no uses of chlorine which we regard as safe.”
~> http://kbda.com/c3/library/rachelchlor.html
You have not explained why the national and International science and health organizations I referenced continue to recognize the benefits of fluoridation or why no such organizations accept the anti-F opinions as legitimate if any of the anti-F evidence was legitimate.
Your so-called “intention of being healthy based on science” is meaningless without any scientific foundation. You have provided nothing.
“Randy Johnson” would put neurotoxic chemicals in my body against my will, even despite countless alternatives.
I agree with a lot of this, you correctly note the serious limitations of research that depends upon ‘correlations’ but you do not go far enough. To clarify, I have to comment on your comparison of what you term;
“Solid Correlation-causation: Smoking and lung cancer.” and “Shaky Correlation-causation: Breakfast and obesity.”
To put it lightly, BOTH are ‘shaky’! The problems associated with the ‘shaky’ are EXACTLY the same with the ‘solid’ – and those problems are many.
The only difference between your ‘solid’ and ‘shaky’ is that your ‘solid’ was effectively the first use of that methodology – it was novel, and several $billions have been spent over several years to disseminate propaganda to reinforce it and promote the ‘everyone knows’ slogan that many have internalised as (wrongly) definitive. The ‘shaky’ is a mere a copy of the ‘solid’.
“Evidence for the increased-risk causation is solid, starting with statistical studies in the 1950s.”
In the 1950s there were very few NON smokers – how many of that cohort were NON smokers? 1950s epidemiological ‘evidence’, and repetitions of the same, is the ONLY evidence suggesting harm. No other research using alternative methodologies have corroborated those early correlations and as smoking prevalence has declined, there are now far more NON smokers who die from lung cancer (over 80% are never and ex-smokers)). ie the correlation is now an inverse one – smoking has NEVER been proven to have caused any harm!
Correlations can never prove causation, they can only ever ‘suggest’ a ‘possible’ link. It does however provide the propagandist with any number of possibilities to manipulate the publics consciousness, as you point out with “If I was a doctor…” comment.