Overgeneralization is the use of small and/or non-representative samples of real data to make an inference that is incorrect. It is considered a cognitive bias, a logical fallacy, and a misuse of statistics.
- Limited sample size:
- -Three senior citizens died after receiving swine flu vaccine in 1976
- -Vaccines are bad for you.
What isn't stated is that 48,161,019 people were immunized, only 532 had any negative reactions after the vaccinations (.001%). Eventually 25 people had fatal reactions from Guillain–Barré syndrome, which was an unknown reaction to a relatively new vaccination at the time. By contrast it is estimated at least 50 million (high estimates put it at near 100) people died from the 1918 swine flu epidemic.
- Non-representative samples:
- -There have been a number of scandals involving financial firms committing fraud.
- -All financial firms and workers are thieves stealing money from society.
- Stereotyping is an example of overgeneralization based on personal characteristics of a single person or small groups.
- -MS-13 is a ultra violent South American criminal gang.
- -All Latinos are in violent gangs...or to Stormfront all minorities.
- Misunderstanding of the simple definition of words:
- -Heroin and Meth are addictive substances and harm the body.
- -All drugs are addictive and harmful.
"Drugs" is a word so general that it includes a wide category from very nasty substances like Heroin/Meth, relatively benign substances like caffeine/alcohol, to very useful pharmaceuticals like antibiotics.
 Overgeneralization as a defense for cranks
In a mixture with the association fallacy, overgeneralization has been used to ward off criticisms of wingnuts in an attempt to associate themselves with more mainstream groups. It is often used to portray the entire fringe group as "victims" of the attack, in order to motivate a larger group to respond in their defense.
- Stormfront and other neo-nazi groups often try to portray attacks against their hate as an attack against all Caucasians or all Christians.
- Survivalists often claim that criticizing their constant rants that the end of the world is nearly here is a criticism of making preparations for emergencies encouraged by governmental agencies. More sane people have started calling themselves "Preppers" in an attempt to stop this overgeneralization.
- In a
stunningnormal display of claiming to be a victim of media criticism, Sarah Palin has claimed that any criticism of what she says in a misogynistic attack against all women.