Editing Selection bias (section)

{{short description|Bias in a statistical analysis due to non-random selection}}
'''Selection bias''' is the [[bias]] introduced by the selection of individuals, groups, or data for analysis in such a way that proper [[randomization]] is not achieved, thereby failing to ensure that the sample obtained is representative of the population intended to be analyzed.<ref>[http://www.cancer.gov/dictionary?CdrID=44087 Dictionary of Cancer Terms → selection bias]. Retrieved on September 23, 2009.</ref> It is sometimes referred to as the '''selection effect'''. The phrase "selection bias" most often refers to the distortion of a [[statistical analysis]], resulting from the method of collecting samples. If the selection bias is not taken into account, then some conclusions of the study may be false.