"Anecdata" redirects here. For the citizen science portal, seeAnecdata.org.
Anecdotal evidence (oranecdata[1]) isevidence based on descriptions and reports of individual, personal experiences, or observations,[2][3] collected in a non-systematic manner.[4]
The termanecdotal encompasses a variety of forms of evidence, including personal experiences, self-reported claims,[3] eyewitness accounts of others,[5] and those from fictional sources, making it a broad category that can lead to confusion due to its varied interpretations. Anecdotal evidence can be true or false but is not usually subjected toscholarly methods,scientific methods, or rules of legal, historical, academic, orintellectual rigor, meaning there are little or no safeguards againstfabrication or inaccuracy.[2] However, the use of anecdotal reports inadvertising or promotion of a product, service, or idea may be considered atestimonial, which is highly regulated in certain jurisdictions.[6]
The persuasiveness of anecdotal evidence compared to that of statistical evidence has been a subject of debate; some studies have argued that there is a generalized tendency to overvalue anecdotal evidence, whereas argue the contrary.[7][8][9][10][11]
"information passed along by word-of-mouth but not documented scientifically"[13]
"evidence that comes from an individual experience. This may be the experience of a person with an illness or the experience of a practitioner based on one or more patients outside a formal research study"[14]
"the report of an experience by one or more persons that is not objectively documented or an experience or outcome that occurred outside of a controlled environment"[15]
Anecdotal evidence may be considered within the scope ofscientific methods. Some anecdotal evidence can be both empirical and verifiable, e.g.,case studies in medicine. Other anecdotal evidence does not qualify asscientific evidence because its nature prevents it from being investigated by the scientific method, such asfolklore or intentionally fictional anecdotes. Anecdotal evidence is considered the least certain type ofscientific information.[16] Researchers may use anecdotal evidence for suggesting newhypotheses but never as validating evidence.[17][18]
Anecdotal evidence varies in formality. For instance, in medicine, published anecdotal evidence by a doctor like acase report is subjected to formalpeer review.[19] Although such evidence is seen as inconclusive, researchers sometimes regard it as an invitation to more rigorous scientific study.[20] For instance, one study found that 35 of 47 anecdotal reports of drug side effects were later sustained as "clearly correct".[21]
Where only one or few anecdotes are presented, they risk being unreliable due tocherry-picking or otherwisenon-representative sampling.[22][23] Similarly, psychologists have found that due tocognitive bias, people are more likely to remember notable or unusual examples.[24] Thus, anecdotal evidence is not necessarily representative of a typical experience even when accurate. Determination of whether an anecdote is typical requiresstatistical evidence.[25] Misuse of anecdotal evidence in the form of argument from anecdote is aninformal fallacy[26] and is sometimes referred to as the "person who" fallacy, with statements like "I know a person who..." or "I know of a case where...". This places undue weight on possibly atypical experiences of close peers. If an anecdote illustrates a desired conclusion rather than a logical conclusion, it is considered afaulty generalization.[27]
In the legal sphere, anecdotal evidence, if it passes certain legal requirements and is admitted astestimony, is a common form of evidence used in a court of law. In many cases, anecdotal evidence is the only evidence presented at trial.[29]
For a testimony to be considered evidence, it must be givenunder oath, where the individual swears they only testify to their words and actions. Someone intentionally lying under oath is subject toperjury. However, these legal rigors do not make testimony in a court of law equal toscientific evidence. Testimony about another person's experiences or words is termedhearsay and is usually not admissible. However, hearsay that is not objected to by a judge is considered evidence for ajury. This means trials contain a considerable amount of anecdotal evidence that juries find relevant.Eyewitness testimony, a type of anecdotal evidence, is considered the most compelling form of evidence by a jury.[30]
^abIrwig, Les; Irwig, Judy; Trevena, Lyndal; Sweet, Melissa (2008),"The weakness of one",Smart Health Choices: Making Sense of Health Advice, Hammersmith Press, retrieved2024-10-03
^Lilienfeld, Scott O.; Lynn, Steven Jay; Lohr, Jeffrey M. (2014)."Initial Thoughts, Reflections, and Considerations".Science and Pseudoscience in Clinical Psychology (2 ed.). New York: Guilford Publications. p. 9.ISBN9781462517510.Testimonial and anecdotal evidence can be quite useful in the early stages of scientific investigation. Nevertheless, such evidence is almost always much more helpful in the context of discovery (i.e., hypothesis generation) than in the context of justification (i.e., hypothesis testing [...]).
^Gibson, Rhonda; Zillman, Dolf (1994). "Exaggerated Versus Representative Exemplification in News Reports: Perception of Issues and Personal Consequences".Communication Research.21 (5):603–624.doi:10.1177/009365094021005003.S2CID145050644.
