Hasty Generalization

The hasty generalization is an informal fallacy in which an inductive generalization is made from a sample that is inadequate to support the generalization in the conclusion. As discussed in the post on inductive generalization, this may be because the sample is too small or biased.

Hasty generalizations often result from anecdotal arguments, which are short stories typically taken from the personal experience of the arguer. Generally, these anecdotal arguments describe only one or a few episodes which are then used to generalize about the population.

For example:

"Acupuncture works. My friend Tom tried it and he said it cured his back pain.".

or

"Smoking isn't harmful. My dad smoked a pack a day and lived until 95."

When countering an argument which uses a hasty generalization the book "Attacking Faulty Reasoning" suggests using an absurd example to demonstrate the flaw. For example,

“Faculty kids are real brats. I babysat with one the other night, and he was spoiled, rude, and uncontrollable.”

If necessary, put the argument into standard form:
Since the faculty child I babysat for recently was a brat, (premise)
[and one faculty child is a sufficient sample of faculty children to determine what is true of all faculty children,] (implicit premise)
Therefore, all faculty children are brats. (conclusion)


The Nizkor Project: Hasty Generalization
Fallacy Files: Hasty Generalization
Attacking Faulty Reasoning