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Selection bias

Selection bias is the error of distorting a statistical analysis by unconsciously or fraudulently pre- or post-selecting the samples. Typically this causes measures of statistical significance to appear much stronger than they are, but it is also possible to cause completely illusory artifacts. Selection bias can be much more difficult to detect than forms of scientific fraud which manipulate data directly, and even when detected it is often impossible to prove that the manipulation was conscious.

There are many types of possible selection bias, including:


Space: Data: Participants: Studies: Selection bias is closely related to: See also: bias (statistics)