Anyone who ever had any interest in science will know that anecdotal evidence is the worst type of evidence possible. This is what scientists and science teachers repeatedly tell their audience.
But is this statement true? If you have a look at the subject matter closely, it doesn't appear to be so.
There are many situations where anecdotal evidence is the best evidence possible. In fact, even the most hardcore scientists use it regularly for very important life decisions.
There are certain aspects of reality that are extremely hard to research scientifically. And there are those aspects of reality that the mainstream science refuses to research. For both of those, anecdotal evidence is the only evidence available.
On the other hand, there are areas of science that deem anecdotal evidence perfectly acceptable. And there is an important reason for it - those branches of science would cease to exist otherwise.
In this article, you will find out how anecdotal evidence received its bad reputation and why you shouldn't always trust those people who say it's bad.
What is anecdotal evidence
Collins dictionary defines anecdotal evidence as follows:
-Anecdotal evidence is based on individual accounts, rather than on reliable research or statistics, and so may not be valid.-
So, essentially, if a person or a group of people have suggested that something works in a particular way, but this phenomenon has never undergone thorough research in accordance with the standards of the modern scientific method, the reports that people have provided is classed as anecdotal evidence.
For example, somebody may notice that planting garlic next to strawberries will prevent slugs from eating the strawberries. However, until a proper research is done to find out if any substances inside garlic have repellent effect on slugs, these accounts are classed as anecdotal evidence.
Another type of anecdotal evidence is information you may receive from authors of self-help books. When the author says that he was able to use particular steps to get from poverty to riches, he may not be lying. The steps may have genuinely helped him. However, this wouldn't necessarily mean that the same steps, if taken by someone else, will produce the same results.
There are important distinction between the two examples. It would be fairly straightforward to conduct a proper scientific research to confirm or deny whether garlic has any slug-repellent properties. However, it would be next to impossible to validate whether subjective life choices of an individual over his lifetime can reliably yield similar outcomes in another individual.
So, the answer to the question of whether or not one should rely on anecdotal evidence is not that simple. Let's have a closer look various types of anecdotal evidence, so you can make that decision for yourself.
Certain topics are impossible to research
It is well known that, when scientific experiments are done on human subjects, both knowledge of the subject which group they belong to and the knowledge of the researchers which group any particular subject belongs to may affect the results of the experiment. Therefore, according to the best practices in science, any experiments involving human subjects has to use double blind tests, where neither the subjects nor the researchers that work with the subjects know who belong in which group.
Because of these, any anecdotal evidence that is based on purely subjective experience is extremely hard, or sometimes is outright impossible to research by using the correct scientific procedures.
Science is a methodology that is designed to find the objective truth, which will remain the truth regardless of individual experiences. Subjective experience, however, doesn't mean that something is objectively true. It merely means that a particular person perceives something as the truth.
One notorious example of anecdotal evidence that is impossible to validate scientifically is the concept of The Law of Attraction that is popularised by self-help industry and that many successful people swear by.
"The Law of Attraction" suggests that your predominant thought patterns attract circumstances to you in your physical reality. For example, if you constantly think about how awful it would be to get mugged, one day you will get mugged. On the other hand, if you are currently living in poverty, thinking that you really are wealthy and poverty is just a temporary condition will attract to you the opportunities to earn real wealth.
The concept may or may not work, but there is no way to find it out scientifically. Therefore, it may be worth to take it seriously if a successful person you trust talks about it in a positive way. However, you should never trust any person who claims that "The Law of Attraction" is fully supported by science, especially if such person wants to sell you something.
Why science refuses to research certain topics
However, not all anecdotal evidence remains anecdotal purely because it's impossible to research by science. Sometimes, it is fairly easy to come up with a proper scientific experiments to confirm or disprove the anecdotes. Despite this, mainstream science would refuse to conduct such experiments. And there are two key reasons behind it - conflict of interest and dogmatism.
Contrary to the popular belief, science does not just consist of disinterested open-minded people who are trying to get to the objective truth. Research funding has to come from somewhere and the funding is allocated only to the research that the funding organisation is interested in.
This is why, for example, the ability of people to heal themselves purely by the power of believe that is well-known to science as " placebo effect " remains just a little inconvenience for medical researchers rather than something that gets thoroughly researched itself.
Placebo effect is often perceived as something negative; for example, as an evidence that a given experimental drug didn't work. But if you think carefully about what placebo effect is, you will realise that it's a hidden ability of an organism to heal itself by some sort of mind-body connection.
And placebo effect isn't merely about curing yourself from the symptoms of common cold without any medical intervention. There were enough confirmed cases where people were able to get rid of some very serious health conditions purely by the power of believe.
So, if human body potentially has a powerful ability to heal itself without any side effects and, in some cases, do it better than the medicine can, why isn't this ability researched properly? After all, it's type of a research than you can do by following proper scientific procedures. For example, you can use statistics to determine whether particular types of changes in the subject's environment make self-healing more effective.
The reason is very simple. The main source of finding for medical research is pharmaceutical industry, whose revenue depends on the sale of drugs. After all, it's the drugs that are developed by the pharmaceutical corporations that get tested in the labs.
People who run the industry realise that conducting research on how to make the process of self-healing effective and reliable may make large chunks of pharmaceutical industry obsolete. Therefore, we will unlikely to ever see any substantial funding for such research. And even if someone would conduct such research and come up with useful results, the publications produced by it would have probably been drowned in other types of medical research, so would be extremely difficult to find.
Another example of a topic that science would not eagerly research is the potential ability of people to improve their eyesight purely by exercises. There is plenty of anecdotal evidence to indicate that it's possible. Bates Method is perhaps the best known way of achieving this.
Ophthalmologists do criticise these methods, but they have never been decisively disproved by a proper scientific research. And the reason why such research has never been conducted can be explained by the fact that ophthalmology gets funded by the sale of glasses and various other interventional eyesight correction procedures. If it suddenly becomes known that the eyesight can be corrected just by doing some exercises for ten minutes a day, majority of people will no longer need glasses, so there will be not as much need for ophthalmology.
These were examples of the cases where scientists will refuse to conduct proper scientific experiments because it's not in their pragmatic interest to do so. However, sometimes scientists will not research a certain topic purely because their own religion-like dogmatism.
Although scientists do criticise religion as dogmatic while presenting themselves as open-minded, scientists are not free from dogmatism themselves. In science, a set of dogmas is known as a paradigm.
Being able to feel someone's stare is an example of a topic that very few mainstream scientists would be willing to research. Many people, myself included, have reported that they have felt an urge to turn in a particular direction, only to cach someone staring at them. Likewise, people have been reporting being able to get strangers to turn around by staring at them.
And this is something that isn't difficult to research at all. For example, I was able to conclude for myself that the phenomenon is real. By doing a little experiment.
I would start by positioning myself in the far end of a room on a ground floor of a building facing a busy pedestrian path. There was no way that anyone walking on the path would be able to notice me in their peripheral vision, as I was positioned at 90° angle to the path and hidden by the walls. Despite this, almost every passerby that I started at turned their head to face me.
Since then, I have conducted some further mini experiments of this sort with similar results, so I have concluded for myself that the phenomenon is real. Yet, according to the dominant scientific paradigm, it would be impossible, so no serious research would ever be done on it.
The dominant scientific paradigm states that our vision is nothing but projection of certain wavelengths of light on our retinas. As the eyes themselves supposedly don't project anything, it would not be possible to feel someone's stare.
Another subject that is supported by a lot of anecdotal evidence that scientists will never touch is telepathy - the ability to know something that you can't possibly have physical access to, which includes the ability to read people's thoughts. And, once again, it is something that can be researched scientifically.
According to the dominant scientific paradigm, mind is nothing but a function of a brain; therefore it would be impossible for the mind to experience something that brain doesn't have access to via one of its numerous sensors.
Experiments have done on a small scale by various open-minded scientists and some of them have provided strong evidence that telepathy is real. For example, an experiment on dogs has confirmed that they often know when their owner is about to return to the house, while the presence of the owner cannot yet be detected by either smell or hearing.
Rupert Sheldrake, a biologist with several decades of experience, talks about dogmatism in science quite extensively. He has ever coined a term "Scientism", which is like a science-based religion that is, just like any other religion, is governed by strictly enforced dogmas.
In his book, "The Science Delusion ", he talks about such dogmatism and how it hiders the science from being truly innovative. This would be essential reading for a true science enthusiast who would be open minded enough to assess these ideas critically instead of just rejecting them outright.
How anecdotal evidence can complete the picture
Regardless of why certain subjects are only supported by anecdotal evidence, sometimes it's the only evidence available and the picture will be incomplete without it.
For example, statistics say that people in Britain who are born into lower socio-economic class tend to stay in that class, unlike in many other European countries, where people tend to move up the socio-economic ladder. This is something that is well researched by science, as proper statistical analysis was used.
However, this data in itself is insufficient to make any meaningful conclusion. Yes, you may hear people saying that the data proves that working class kids in Britain lack opportunities. Those who say such thing are committing logical fallacy of confusing correlation with causation.
There are plenty of alternative explanations for the data being what it is and it is very important to know the causes, as the solutions to the problem will be different depending on what the cause is.
For example, if working class kids genuinely lack opportunities, then the solution would be to ensure that sufficient educational facilities are supplied in disadvantaged areas. If, on the other hand, it's the culture within working class communities that prevents the kids from taking these opportunities even when they are widely available, then some degree of social engineering would probably be necessary to change the culture.
And if there is no properly obtained scientific evidence to find out which of the explanations is correct, we will have no choice but to rely on anecdotal evidence. This will, at least, improve our chances of getting to the truth, while the alternative would be just to have a random guess.
As someone who has spent teenage years growing among English working class people, I came to the conclusion that the real cause of lack of social mobility within their community is crab bucket culture rather than any genuine lack of opportunities for the kids to better themselves.
"Crab bucket theory" states that if you place one crab into a bucket, it will just escape, while if you place many crabs into the same bucket, they will keep pulling each other down, so nobody would escape. And pulling each other down is what I have seen regularly happening in working class communities.
Being an outsider with a different upbringing, I had no problem not succumbing to that culture, despite being financially in exactly the same situation as my working class peers. And, despite my financial constraints, I had no problem obtaining good education and eventually starting a well-paid career in an in-demand field of software development.
And I don't consider myself a unicorn. I know plenty of people who took very similar approach and achieved similar results despite the same unfavorable start. So, I don't believe that the UK lacks opportunities for working class kids to build fulfilling lives for themselves.
Of course, what I have just presented is an anecdotal evidence. And I do realise that my experience may have been specific to a small geographic area rather than the whole country. But I would say that my first-had experience in this situation, if confirmed by reported first-hand experience of other people from similar background, is much more reliable that a statement from someone who was born into middle class and has never set his foot into a disadvantaged area. Such person would just be making a guess by applying one of many possible interpretations behind the data.
The reason why this matters is that, if we get the source of the problem wrong, we will waste a lot of public money, while the problem would remain. If we already have more than enough colleges and trade schools that are accessible to anyone, building more would be futile. Publicising the fact that these schools can help people to obtain well-paid in-demand jobs, teaching school kids that it's realistic to move up the socio-economic ladder and teaching them how to resist peer pressure from the people who don't want the best for them would be much more effective strategy.
How whole branches of science are held together by anecdotal evidence
Scientists will define anything that claims to be science, yet doesn't follow proper scientific procedures, as pseudoscience. There are, however, some fields of science that have been spared the definition, despite being largely based on little more than anecdotal evidence.
Psychology and sociology (especially sociology) are largely based on anecdotal evidence, yet very few people question their validity.
In both of these fields, people are asked to fill questionnaires to provide data for the research. But what are the questionnaires, other than report of subjective experience that would be classed as anecdotal evidence in any other branch of science.
There is a famous TED talk that describes a couple of sociological experiments that were performed by a reputable scientific institution, the University of California, Berkeley. The conclusion of the experiments was that as we become wealthier, we become meaner. However, none of these experiments have followed proper scientific principles, such as double-blind trials or even the use of control groups.
In one of the experiments, students were invited to play a game of Monopoly. What was unknown to them is that the game was rigged in favour of one of them. And, whenever a particular player would start getting clearly ahead, he would exhibit the signs of dominant behaviour. Once the game was finished, the winner would say that it was their tactics that got them to win, not that they have realised that the game was rigged.
In this experiment, people who observed the students were aware whose favour the game was rigged in. And there was no control group where people played unrigged sessions of Monopoly. And the whole subject group was homogeneous and consistent purely of young university student who were mainly men, so there was no consideration given to any other factors that could have affected the results.
Yet, according to the standards of sociology, the methodology was perfectly valid and sufficient to make the conclusions that were made - that money makes people mean. This is despite the fact that there wasn't even any money involved in the experiment, except for Monopoly money.
Another experiment was done to see whether wealthier people were more likely to break the law. To determine this, a camera was placed next to a zebra crossing. By law, pedestrians at such crossings were given priority and the drivers were supposed to stop once a pedestrian sets foot on the crossing.
A researcher would cross the road as some car was about to drive past. And if the car failed to stop for the researcher, it's make and model was recorded. Expensive cars were later used as a proxy indicator of the wealth of its driver.
It was found that more of the expensive cars were failing to stop compared to cheaper ones. Therefore it was concluded that wealthier people are more likely to be willing to break the law.
However, once again, the methodology was anything but scientific. Double blind principle wasn't employed, so a researcher could have influenced the outcome by either stepping on the crossing too late for the car to stop safely, or standing on it in such a way that the driver wouldn't easily notice him, which appeared to be the case in some of the videos shown in the TED talk.
Likewise, nobody considered other factors. Perhaps, it's those people who spend more time on the road and not necessarily the wealthiest who are more likely to drive past the pedestrian. This was suggested in one of the videos by a bus failing to stop for the pedestrian as well.
Finally, what if it was just an area where expensive cars significantly outnumbered inexpensive ones? What about having a control run in a poorer area to see if it's the total proportion of drivers that are less likely to stop for the pedestrians and not just the drivers of expensive cars?
So, next time you hear some statements of fact coming from the practitioners of social sciences (psychologists, sociologists, political scientists, etc.), take it with a massive grain of salt and look up the source yourself.
Even scientists rely on anecdotal evidence for important life decisions
Even when someone says that anecdotal evidence should never be relied on, they themselves are definitely relying on it for some of their most important life decisions.
Take learning to drive, for example. Your driving instructor will use specific methods of teaching not because he has read a peer-reviewed scientific paper on what teaching methods are the most effective, but because he has learned through experience that particular methods work better than others. Therefore, when you decide to earn your driving license, you will be completely at mercy of someone's anecdotal evidence.
Despite this, you will probably never hear any complaints from qualified scientists. Whenever any of them need to learn to drive, they will do it in the same way everyone else does.
Another important life decision everyone takes is a choice of romantic partner. There is no proper scientific way of determining what kind of person would suit you the best. You will either have to rely on your own experience or experience of other people. And scientists are not exception.
Even the scientists will follow their gut feelings to make important life decisions. Even scientists will ask opinion of their friends (read: directly ask for anecdotal evidence). So, if they are not shying away from anecdotal evidence, why should you?
Proceed with caution
As we saw, anecdotal evidence can be the best source of information you can rely on. Sometimes, there is just no way to research an issue scientifically, so anecdotal evidence is all you are left with. On other occasions, the issue would not be researched scientifically because doing so may put the competent authorities at risk.
Having said that, you should never just trust any random anecdotal evidence. Scientists are correct when they say that, due to its nature, anecdotal evidence may be fabricated or simply be a result of misperception or misinterpretation.
To find out whether any particular piece of anecdotal evidence should be relied on, you can do a simple cost-benefit analysis: how much would you potentially gain if a particular phenomenon is true versus how much would you loose if it's false.
Take the ability to improve your eyesight via exercises. No ophthalmologists has ever said that you can achieve it, but plenty of people said that you can. If you are short-sighted or long-sighted, you could do eye exercises for 10-15 minutes every day, or keep regularly buying pairs of glasses and/or contact lenses either for the rest of your life, or until you have forked out a huge sum of money on an expensive laser surgery.
In my opinion, 10-15 minutes of your time daily is a small price to pay for not having to wear glasses ever again. And if you do it for a prolonged period of time and found out the exercises don't work, you can just stop spending the time that you would have probably otherwise spent scrolling your Facebook feed anyway.
The same applies to The Law of Attraction. The concept states that if you vividly imagine yourself being in possession of what you want, then you will eventually attract it to yourself.
Again, it would cost you nothing to try it out for yourself. If anything, if done properly, it will make you a more positive person. Likewise, if you convince yourself that a particular goal is achievable, you will work towards it more willingly and will improve your chances of achieving it through hard work alone.
Law of Attraction doesn't imply that you should just twiddle your thumbs until the thing you think about falls into your lap. Connor McGregor uses The Law of Attraction to convince himself that all the hard work he puts out in the MMA gym will pay off.
Another good example would be a homeopathic remedy. Homeopathy is not accepted as a proper science by the mainstream scientific community, but you may have people telling you that a particular homeopathic remedy has helped them.
If you have a hay fever and a homeopathic remedy that claims to be able to relieve its symptoms is cheap, why not try it? In the worst-case scenario, you will just loose some small change and will make your mind up about the validity of homeopathy. In the best-case scenario, your unpleasant symptoms will disappear.
However, whenever somebody claims that a particular technique based purely on anecdotal evidence is truly scientific and expects a hefty sum of money to teach you the technique, I would probably stay away. It's likely to be a scam.
Or maybe someone is not even asking your for money, but makes a claim that particular risky action would gain you the riches. In this case, if the possibility of failure is too high and the potential consequences of failure are too dear, you should probably ignore this advise.
Likewise, if someone is making a claim based on anecdotal evidence, but a clear-cut scientific evidence exists to refute than claim, I would not accept the anecdotal evidence.
Having said that, there is an important difference between something being refuted by scientific evidence and no scientific evidence being available to prove that something works. Homeopathy, for example, belongs to the latter category. So does the existence of God.
Now, you are better equipped to make good decisions when only limited amount of imperfect information is available. Good luck!
Written by Fiodar Sazanavets
Posted on 27 Jul 2019