Hasty generalization
Hasty generalization is a logical fallacy of faulty generalization
Faulty generalization
A fallacy of defective induction reaches a conclusion from weak premises. Unlike fallacies of relevance, in fallacies of defective induction, the premises are related to the conclusions yet only weakly buttress the conclusions. A faulty generalization is thus produced...

 by reaching an inductive
Inductive reasoning
Inductive reasoning, also known as induction or inductive logic, is a kind of reasoning that constructs or evaluates propositions that are abstractions of observations. It is commonly construed as a form of reasoning that makes generalizations based on individual instances...

A generalization of a concept is an extension of the concept to less-specific criteria. It is a foundational element of logic and human reasoning. Generalizations posit the existence of a domain or set of elements, as well as one or more common characteristics shared by those elements. As such, it...

 based on insufficient evidence
Evidence in its broadest sense includes everything that is used to determine or demonstrate the truth of an assertion. Giving or procuring evidence is the process of using those things that are either presumed to be true, or were themselves proven via evidence, to demonstrate an assertion's truth...

essentially making a hasty conclusion without considering all of the variables. In statistics
Statistics is the study of the collection, organization, analysis, and interpretation of data. It deals with all aspects of this, including the planning of data collection in terms of the design of surveys and experiments....

, it may involve basing broad conclusions regarding the statistics of a survey
Statistical survey
Survey methodology is the field that studies surveys, that is, the sample of individuals from a population with a view towards making statistical inferences about the population using the sample. Polls about public opinion, such as political beliefs, are reported in the news media in democracies....

 from a small sample group
Sampling (statistics)
In statistics and survey methodology, sampling is concerned with the selection of a subset of individuals from within a population to estimate characteristics of the whole population....

 that fails to sufficiently represent an entire population. Its opposite fallacy is called slothful induction
Slothful induction
A slothful induction is a fallacy in which an inductive argument is denied its proper conclusion, despite strong evidence for inference. The opposite fallacy is the hasty generalization.-Examples:-External links:*...

, or denying the logical conclusion of an inductive argument (e.g. "it was just a coincidence").

Context is also relevant; in mathematics, the Pólya conjecture
Pólya conjecture
In number theory, the Pólya conjecture stated that 'most' of the natural numbers less than any given number have an odd number of prime factors. The conjecture was posited by the Hungarian mathematician George Pólya in 1919, and proved false in 1958...

 is true for numbers less than 906,150,257, but fails for this number. Assuming something to be true for all numbers when it has been shown for over 906 million cases would not generally be considered hasty, but in mathematics a statement remains a conjecture
A conjecture is a proposition that is unproven but is thought to be true and has not been disproven. Karl Popper pioneered the use of the term "conjecture" in scientific philosophy. Conjecture is contrasted by hypothesis , which is a testable statement based on accepted grounds...

 until it is shown to be universally true.

Hasty generalization can also be a basis for racist beliefs and prejudice
Prejudice is making a judgment or assumption about someone or something before having enough knowledge to be able to do so with guaranteed accuracy, or "judging a book by its cover"...

s, in which inferences regarding a large group is based upon knowledge of only a small sample size of that group. For example, stereotypical
A stereotype is a popular belief about specific social groups or types of individuals. The concepts of "stereotype" and "prejudice" are often confused with many other different meanings...

 notions that are portrayed in mass media
Mass media
Mass media refers collectively to all media technologies which are intended to reach a large audience via mass communication. Broadcast media transmit their information electronically and comprise of television, film and radio, movies, CDs, DVDs and some other gadgets like cameras or video consoles...

, such as a given person who is Jewish is also inherently greedy, the notion of a person being black equates to that person being poor and/or criminal, or the notion that a caucasian person is therefore lacking in style are all logical fallacies. This includes positive racist ideologies as well, such as the belief that Asians are better off academically than other racial sectors.


  • A person travels through a town for the first time. He sees 10 people, all of them children. The person then concludes that there are no adult residents in the town.

Alternative names

The fallacy is also known as the fallacy of insufficient statistics, fallacy of insufficient sample, generalization from the particular, leaping to a conclusion, hasty induction, law of small numbers, unrepresentative sample, and secundum quid. When referring to a generalization made from a single example it has been called the fallacy of the lonely fact
or the proof by example fallacy.

When evidence is intentionally excluded to bias the result, it is sometimes termed the fallacy of exclusion and is a form of selection bias
Selection bias
Selection bias is a statistical bias in which there is an error in choosing the individuals or groups to take part in a scientific study. It is sometimes referred to as the selection effect. The term "selection bias" most often refers to the distortion of a statistical analysis, resulting from the...


See also

  • Accident (fallacy)
    Accident (fallacy)
    The logical fallacy of accident is a deductive fallacy occurring in statistical syllogisms when an exception to a rule of thumb is ignored. It is one of the thirteen fallacies originally identified by Aristotle...

  • Blind men and an elephant
    Blind Men and an Elephant
    The story of the blind men and an elephant originated in India from where it is widely diffused. It has been used to illustrate a range of truths and fallacies...

  • Categorical imperative
    Categorical imperative
    The Categorical Imperative is the central philosophical concept in the moral philosophy of Immanuel Kant, as well as modern deontological ethics...

     redirected from "Generalization in Ethics"
  • Cognitive distortion
    Cognitive distortion
    Cognitive distortions are exaggerated and irrational thoughts identified in cognitive therapy and its variants, which in theory perpetuate certain psychological disorders. The theory of cognitive distortions was first proposed by Aaron T. Beck. Eliminating these distortions and negative thoughts is...

  • Converse accident
    Converse accident
    The logical fallacy of converse accident is a deductive fallacy that can occur in a statistical syllogism when an exception to a generalization is wrongly called for.For example:The inductive version of this fallacy is called hasty generalization...

  • Generalization (logic)
    Generalization (logic)
    In mathematical logic, generalization is an inference rule of predicate calculus. It states that if \vdash P has been derived, then \vdash \forall x \, P can be derived....

  • Generalization error
    Generalization error
    The generalization error of a machine learning model is a function that measures how far the student machine is from the teacher machine in average over the entire set of possible data that can be generated by the teacher after each iteration of the learning process...

  • Hypercorrection
    In linguistics or usage, hypercorrection is a non-standard usage that results from the over-application of a perceived rule of grammar or a usage prescription...

  • Problem of induction
    Problem of induction
    The problem of induction is the philosophical question of whether inductive reasoning leads to knowledge. That is, what is the justification for either:...

  • Slothful induction
    Slothful induction
    A slothful induction is a fallacy in which an inductive argument is denied its proper conclusion, despite strong evidence for inference. The opposite fallacy is the hasty generalization.-Examples:-External links:*...

  • Statistical significance
    Statistical significance
    In statistics, a result is called statistically significant if it is unlikely to have occurred by chance. The phrase test of significance was coined by Ronald Fisher....

  • Syllogism
    A syllogism is a kind of logical argument in which one proposition is inferred from two or more others of a certain form...

External links

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