Home Theories Anecdotal fallacy

Anecdotal fallacy

Reviewed by expert Scientifically proven

When someone makes an argument based on anecdotal evidence, they commit the anecdotal fallacy. It's a prevalent form of blunder that may be seen in a wide range of ideas. Furthermore, it is frequently committed because of a lack of reasoning abilities; nonetheless, it may be a discussion technique on purpose.

Table of contents:
  1. Why Is It Improper to Rely on Anecdotal Evidence?
  2. What Is an Anecdotal Fallacy?
  3. Post hoc
  4. Hasty Generalization
    1. How does anecdotal fallacy affect sales?
    2. The buyer level
    3. The salesperson level
    4. The confirmation bias at the strategic level
    5. How Statistics Beats Anecdotal Evidence
  5. Conclusion:

Why Is It Improper to Rely on Anecdotal Evidence?

When someone makes an argument based on anecdotal evidence, they commit the anecdotal fallacy. It's a prevalent form of blunder that may be seen in a wide range of ideas. Furthermore, it is frequently committed because of a lack of reasoning abilities; nonetheless, it may be a discussion technique on purpose.

As a result, taking the time to understand how this logical fallacy works and when it occurs may be beneficial to virtually anyone: it can assist in recognizing and opposing the abuse of anecdotal evidence, which can enhance one's arguments and decision-making.

The "Volvo fallacy," "evidence by selected cases," and the "person who fallacy" are all names for this logical mistake.

What Is an Anecdotal Fallacy?

When someone utilizes proof that depends on personal testimonials, such as a narrative based on someone's own experience, to support or disprove a proposition, they commit the fallacy of anecdotal evidence.

To put it another way, the speaker makes a broad conclusion based on a few instances gathered in an informal manner (and often cherry-picked in favor of the argument).

An example of a logical form for such an argument is:

  • Y occurred once when X.
  • As a result, Y will occur whenever X occurs.


  • Person Y said that he had seen/heard X.
  • Therefore, X must be true.

The following is an example of anecdotal fallacy:

  • "Even though my grandpa smoked heavily for most of his life, he lived to be 90 years old. As a result, smoking is not detrimental to humans."

A single person survived to be 100 years old despite smoking is anecdotal evidence and does not imply that smoking is safe. There will be exceptions to the rule in such situations, and pointing out one does not invalidate the norm; only statistical data can show us how familiar something is.

Another issue with anecdotal evidence is that it is vulnerable to cognitive biases in how it is gathered and presented. For example, someone may be impacted by confirmation bias and only bring up models that support their previous opinions, or they may give unjustified credibility to a claim because of our intrinsic predisposition, known as the bandwagon effect, to embrace something because a lot of other people are doing it.

Examples The following is a collection of anecdotal fallacy instances.

  • "Self-driving automobiles are much too unsafe for public roadways." I just read about a deadly collision caused by a self-driving car last week."
  • "Why aren't we using broccoli to treat cancer?" My buddy informed me that cancer patients had been healed after switching to a broccoli-based diet in a few situations."
  • "There is ample proof that God exists: I've heard from a variety of sources that people have become religious after having a personal encounter with God."
  • "For the past two months, my aunt has been on a low-fat diet and has dropped several pounds. She claims it is the most effective diet available."
  • "A lot of people have had paranormal experiences; therefore, it has to be true."

Post hoc

The post hoc fallacy, which is the mistaken belief that one event must have caused another since it occurred before the other, is widely employed in anecdotal evidence arguments.

Post hoc reasoning occurs when someone believes that a specific change in the diet must have caused a subsequent occurrence - such as cancer-free - purely based on the fact that they occurred consecutively, as seen in one of the cases above.

This logic is flawed because, while events that occur in sequence may be causally connected, they can also (and frequently are) be utterly unrelated except that one followed the other.

Hasty Generalization

This is a logical error when a conclusion is drawn based on a small number of cases rather than more reliable statistics.

The fundamental difference between the topic of this article and hasty generalization is that in the former, the instances are carefully chosen to support the argument. In contrast, in the latter, the conclusion is reached based on a too-small sample size accessible to the arguer.

How does anecdotal fallacy affect sales?

Many, if not all, marketing teams aggressively employ the anecdotal fallacy to their advantage. Testimonials, films of satisfied customers, and shining case studies are examples of marketing materials that make use of the brain's fondness for tales and reliance on anecdotes as "proof."

Anecdotal fallacy serves a less visible but equally crucial role in the sales department. Salespeople use it in many of the same ways that marketing does. On the other side, they may face opposition if they prove their product is superior to a competitor. Still, the consumer picks the competition because a friend suggested it.

Let's look at how the anecdotal fallacy effects and may be used at each stage of the sales process:

  • The buyer's behavior (all stakeholders)
  • The salesperson's behavior
  • The manager's behavior
  • Sales leadership sets the strategy, methods, and strategies

The buyer level

The anecdotal fallacy has several consequences for buyers and buying stakeholders. If a buying team member has personal experience with a product or solution or knows someone who does, that experience will inevitably prejudice them. They would prefer it if it were a pleasant experience. They would tend to avoid it if they had a bad experience.

Almost every salesperson has encountered consumers who just refused to look at the proof. They've either determined that your solution won't work because of a personal experience, or they've opted to utilize a different explanation for the same reason.

The salesperson level

Do you have any salesmen on your team who insist on carrying a lucky object or completing rituals, such as tapping a pen on a specific location of their desk or speaking specific phrases before picking up the phone? These behaviors are frequently the result of anecdotal fallacies, in which a person has had a successful call or encounter, and their minds are attempting to make sense of it. The brain frequently clings onto irrelevant information when it lacks rapid access to measures that reveal genuine causation.

The anecdotal fallacy at the manager's level

David Hoffeld recounts an argument he once had with another sales manager in his book (Source: 1) The Science of Selling. They were both sure that a specific technique to marketing was correct. They each taught their salesmen how to use their method, confident that it was the best way to go. Their approaches, however, were opposed. They couldn't possibly be correct at the same time.

This is an illustration of the executive power of the anecdotal fallacy. We all have our own set of experiences and tales that influence how we act and behave.

The confirmation bias at the strategic level

Organizations rely significantly on data, measurements, and figures at the strategic level. You'd assume that strategic leadership would be resistant to the consequences of anecdotal fallacy as a result of this. Regrettably, this is not the case. Regardless of our degree of expertise or responsibility, our brains operate in the same manner. Executives' brains may have been educated to undertake the hard job of statistics, reasoning, and facts, but that doesn't imply their brains will always pick that path.

How Statistics Beats Anecdotal Evidence

In statistics, observational research and randomized controlled trials are the two most common ways for establishing whether a dietary supplement induces weight reduction (RCTs).

Researchers evaluate all relevant factors in a representative sample in an observational study and then develop a statistical model that explains how each variable affects the outcome. You track factors like basal metabolic rate, activity, nutrition, health, and the use of dietary supplements for each participant. You can assess if the accessory connects with weight reduction after taking into account all other relevant variables. Anecdotal evidence does not supply any of this contextual information.

The alternative option is randomized controlled trials (RCTs). RCTs are the gold standard because they enable causal inferences to be drawn regarding the treatment effect. After all, we want to know if the supplement is the reason for the weight reduction. In a randomized controlled trial, patients are assigned to treatment and control groups at random. When therapy begins, this method ensures that the groups are comparable. As a result, differences between groups after the research are most likely due to treatment effects.

Anecdotal evidence may not necessarily be flawed when making judgments. If you ask a buddy for a restaurant recommendation, for example, the risk is modest, especially if you know their preferences. If you're making significant decisions regarding your finances, health, or fitness, though, don't rely on anecdotal evidence. Even though scientific facts and expert analysis aren't as glamorous as emotionally charged stories told by relevant individuals, they're worth considering!


The fallacy of anecdotal evidence mimics this appropriate use of illustrative story-telling. It offers us a scenario in which a conclusion is given to a human face. The error of anecdotal evidence, on the other hand, is when a single example is used instead of a carefully researched study. The fallacy indicates that the anecdote is exhibiting a correctly formed conclusion. In reality, no such properly conducted study exists, or if it does, the tale presented does not accurately represent the study's actual findings.

A new cognitive bias in your inbox every week

You'll get to learn more about CRO and psychology. You'll be able to take experimenting to a whole new level!

* We send our mails on Monday morning btw.

Frequently Asked Questions

Will you use psychology for your experimentation process?

Are you curious about how to apply this bias in experimentation? We've got that information available for you!

Join over 452+ users

  • Lifetime access to all biases
  • Filter on metrics, page type, implementation effort
  • More examples and code for experimentation

Choose your subscription!

Pay with Stripe

Lifetime deal PREMIUM

Get access to the search engine, filter page, and future features.

I want this

Lifetime deal

Get access to the search engine and filter page.

I want this

Do you think you know enough about CRO?

Join our monthly mailing to continue learning more and more about CRO and psychology.