Anecdotal evidence

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Anecdotal evidence is evidence of anecdotes, that is, evidence collected in the usual or informal way and is heavily dependent or wholly on personal testimony. Compared with other types of evidence, anecdotal evidence is generally considered to be of limited value due to a number of potential weaknesses, but may be considered within the scope of the scientific method because some anecdotal evidence may be empirical and verifiable, for example in the use of case studies in medicine. Other anecdotal evidence, however, does not qualify as scientific evidence, because it prevents it from being investigated by the scientific method.

Where only one or more anecdotes are presented, there is a greater possibility that they may be unreliable because of the cherry-selected or non-representative samples of the typical cases. Similarly, psychologists have found that because cognitive biases people are more likely to remember important or unusual examples than typical examples. Thus, even when accurate, anecdotal evidence does not necessarily represent a typical experience. The accurate determination of whether anecdotes are typical requires statistical evidence. The misuse of anecdotal evidence is an informal error and is sometimes referred to as a "mistaken person" ("I know someone who..."; "I know cases where..." etc.) That puts undue burden on a friend's experience - close friends who may be unusual. Compare that with hasty generalizations.

This term is sometimes used in the legal context to describe certain types of testimony that are not supported by objective, independent evidence such as validation documentation, photographs, audio-visual recordings, etc.

When used in advertisements or promotions of products, services, or ideas, anecdotal reports are often called testimonials, which are heavily regulated or prohibited in some jurisdictions.

Video Anecdotal evidence

Introduction

In all forms of anecdotal evidence, its reliability with objective independent judgment may be in doubt. This is a consequence of how informal information is collected, documented, presented, or a combination of all three. This term is often used to describe evidence that there is no documentation, leaving the verification depends on the credibility of the party presenting the evidence.

Maps Anecdotal evidence

Scientific context

In science, the definition of anecdotal evidence includes:

"ordinary observations or indications rather than rigorous or scientific analysis"
"information is forwarded by word of mouth but not scientifically documented"

Anecdotal evidence can have varying degrees of formality. For example, in medicine, anecdotal evidence is published by a trained observer (doctor) called a case report, and subjected to formal peer review. Although such evidence does not appear conclusive, it is sometimes considered an invitation to a more thorough scientific study of the phenomenon. For example, one study found that 35 of 47 anecdotal reports about drug side effects were then maintained as "completely clear."

Anecdotal evidence is considered to be the least specific kind of scientific information. Researchers can use anecdotal evidence to suggest new hypotheses, but never as valid evidence.

Anecdotes, testimonials and urban legends. | Science or not?

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Broken logic

Anecdotal evidence is often unscientific or pseudoscientific because various forms of cognitive bias can influence the collection or presentation of evidence. For example, someone who claims to have met a magical or alien creature can present a very clear story, but this can not be falsified. This phenomenon can also occur in large groups of people through subjective validation.

Anecdotal evidence is also often misinterpreted through heuristic availability, leading to overestimate estimates. If a cause can be easily attributed to an effect, people exaggerate the probable cause of that effect (availability). In particular, clear and emotional anecdotes seem more reasonable, and given greater weight. The related problem is that it is usually not possible to assess any anecdotal evidence, the rate of people not reporting anecdotal evidence in the population.

The general way anecdotal evidence becomes unscientific is through false reasoning such as hoisting ergo propter hoc, the human tendency to assume that if an event occurs after another event, the former must be the second cause. Another error involves inductive reasoning. For example, if an anecdote illustrates a desired conclusion rather than a logical conclusion, it is considered a false or hurried generalization. For example, here is anecdotal evidence presented as evidence of the desired conclusion:

There is ample evidence that drinking water cures cancer. Just last week I read about a girl who was dying of cancer. After drinking water he was healed.

Anecdotes like this do not prove anything. In some cases where several factors influence the probability of an outcome, rather than uniquely determining it, the selected individual cases do not prove anything; eg "My grandfather smoked 40 days until he died at age 90" and "my sister never approached anyone who smoked but died of lung cancer". Anecdotes often refer to exceptions, not rules: "Anecdotes are useless precisely because they may refer to idiosyncratic responses."

More generally, the statistical correlation between things does not necessarily prove that one causes the other (a causal relationship). A study found that television viewing is highly correlated with sugar consumption, but this does not prove that vision causes sugar intake (or vice versa).

In medicine, anecdotal evidence is also subject to a placebo effect: it is certain that the expectations of a patient (or physician) can actually alter the outcome of treatment. Only double-blind placebo-controlled, placebo-controlled trials can confirm hypotheses about the effectiveness of treatment independently of expectations.

In contrast, in science and logic, the "relative strength of explanation" is based on its ability to be tested or repeated, proved by the underlying cause, and can be verified in neutral conditions in a way that other researchers will agree. has been done competently, and can check alone.

What is ANECDOTAL EVIDENCE? What does ANECDOTAL EVIDENCE mean ...

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Legal

Witness testimony is a common form of evidence in law, and the law has a mechanism for testing witness evidence for reliability or credibility. The legal process for taking and assessing evidence is formalized. Some witness testimonials can be described as anecdotal evidence, such as harassment stories as part of a class action lawsuit. However, witness testimony can be tested and assessed for its reliability. Examples of approaches to testing and assessment include the use of questions to identify gaps or inconsistencies, evidence substantiating witnesses, documents, videos and forensic evidence. If the court does not have the appropriate means to test and assess the testimony of a particular witness, such as the absence of forms of proof or proof, it may provide limited or no "weight" testimony when making decisions about facts.

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Scientific evidence as legal evidence

In certain situations, the scientific evidence presented in the court must also meet the legal requirements for evidence. For example, in the United States, the testimony of expert witnesses must meet Daubert's standards. This ruling states that before evidence is presented to witnesses by experts, the methodology should be "generally accepted" among scientists. In some situations, anecdotal evidence can meet this threshold (such as a specific case report that corroborates or refutes other evidence).

Altman and Bland argue that case reports or outlier statistics can not be dismissed because they do not have weight: "With rare and uncommon diseases, the insignificant findings in randomized trials do not necessarily mean that there is no causal relationship between the agent and the disease. "

Logical Fallacy #9: Anecdotal Evidence - YouTube

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References

Let the facts speak for you | Mark's Blog

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Anecdotal evidence

Minggu, 01 Juli 2018