Editing Selection bias (section)

=== Volunteer bias ===
{{main|Self-selection bias}}

Self-selection bias or a volunteer bias in studies offer further threats to the validity of a study as these participants may have intrinsically different characteristics from the target population of the study.<ref>{{Cite journal|last1=Tripepi|first1=Giovanni|last2=Jager|first2=Kitty J.|last3=Dekker|first3=Friedo W.|last4=Zoccali|first4=Carmine|date=2010|title=Selection Bias and Information Bias in Clinical Research|url=https://www.karger.com/Article/FullText/312871|journal=Nephron Clinical Practice|language=english|volume=115|issue=2|pages=c94–c99|doi=10.1159/000312871|issn=1660-2110|pmid=20407272|doi-access=free}}</ref> Studies have shown that volunteers tend to come from a higher social standing than from a lower socio-economic background.<ref name=":0">{{Cite web|date=2017-11-17|title=Volunteer bias|url=https://catalogofbias.org/biases/volunteer-bias/|access-date=2020-10-29|website=Catalog of Bias|language=en}}</ref> Furthermore, another study shows that women are more probable to volunteer for studies than males. Volunteer bias is evident throughout the study life-cycle, from recruitment to follow-ups. More generally speaking volunteer response can be put down to individual altruism, a desire for approval, personal relation to the study topic and other reasons.<ref name=":0" /><ref name="Jordan"/> As with most instances mitigation in the case of volunteer bias is an increased sample size. {{Citation needed|date=January 2021|reason=A citation that mentions that increasing the sample size mitigates this would be beneficial}}