Editing Bias (section)

===Statistical biases===
{{main|Bias (statistics)}}
Statistical bias is a systematic tendency in the process of data collection, which results in lopsided, misleading results. This can occur in any of a number of ways, in the way the sample is selected, or in the way data are collected.<ref>{{cite web |last=Rumsey |first=Deborah J. |author-link= Deborah J. Rumsey |url=https://www.dummies.com/education/math/statistics/how-to-identify-statistical-bias/ |title=HOW TO IDENTIFY STATISTICAL BIAS |publisher=Dummies.com |access-date=2018-08-24 |url-status=live |archive-url=https://web.archive.org/web/20180214195807/https://www.dummies.com/education/math/statistics/how-to-identify-statistical-bias/ |archive-date=2018-02-14 }}</ref> It is a property of a [[statistics|statistical]] technique or of its results whereby the [[expected value]] of the results differs from the true underlying quantitative [[parameter#Statistics and econometrics|parameter]] being [[estimation theory|estimated]].

====Forecast bias====
{{main|Forecast bias}}
A forecast bias is when there are consistent differences between results and the forecasts of those quantities; that is: forecasts may have an overall tendency to be too high or too low.

====Observer-expectancy effect====
{{main|Observer-expectancy effect}}
The observer-expectancy effect is when a [[researcher|researcher's]] expectations cause them to subconsciously influence the people participating in an experiment. It is usually [[experimental control|controlled]] using a [[double-blind experiment|double-blind system]], and was an important reason for the development of double-blind experiments.

====Reporting bias and social desirability bias====
{{main|Reporting bias|Social desirability bias}}
In [[epidemiology]] and [[empirical research]], reporting bias is defined as "selective revealing or suppression of information" of undesirable behavior by subjects<ref name="Porta2008">{{cite book|editor=Porta, Miquel|title=A Dictionary of Epidemiology|url=https://books.google.com/books?id=s7R-MLMyEgwC&pg=PT275|access-date=27 March 2013|date=5 June 2008|publisher=Oxford University Press|isbn=978-0-19-157844-1|page=275|url-status=live|archive-url=https://web.archive.org/web/20161216010931/https://books.google.com/books?id=s7R-MLMyEgwC&pg=PT275|archive-date=16 December 2016}}</ref> or researchers.<ref>[http://www.cochrane.org/resources/handbook/ Green S, Higgins S, editors: Glossary. Cochrane Handbook for Systematic Reviews of Interventions 4.2.5.] {{webarchive|url=https://web.archive.org/web/20100309033953/http://www.cochrane.org/resources/handbook/ |date=2010-03-09 }}</ref><ref>{{cite journal | last1 = McGauran | first1 = N | last2 = Wieseler | first2 = B | last3 = Kreis | first3 = J | last4 = Schüler | first4 = YB | last5 = Kölsch | first5 = H | last6 = Kaiser | first6 = T | year = 2010 | title = Reporting bias in medical research - a narrative review | url = http://www.trialsjournal.com/content/pdf/1745-6215-11-37.pdf | journal = Trials | volume = 11 | page = 37 | doi = 10.1186/1745-6215-11-37 | pmid = 20388211 | pmc = 2867979 | url-status = live | archive-url = https://web.archive.org/web/20160108110151/http://www.trialsjournal.com/content/pdf/1745-6215-11-37.pdf | archive-date = 2016-01-08 | doi-access = free }}</ref>
It refers to a tendency to under-report unexpected or undesirable experimental results, while being more trusting of expected or desirable results. This can propagate, as each instance reinforces the status quo, and later experimenters justify their own reporting bias by observing that previous experimenters reported different results.

Social desirability bias is a bias within [[Social research|social science research]] where [[survey methodology|survey]] respondents can tend to answer questions in a manner that will be viewed positively by others.<ref name="SDRdef">{{cite web | title = Social Desirability Bias | date = 13 November 2011 | publisher = psychologyconcepts.com | url = http://www.psychologyconcepts.com/social-desirability-bias/ | access-date = September 1, 2015 | url-status = live | archive-url = https://web.archive.org/web/20150831110944/http://www.psychologyconcepts.com/social-desirability-bias/ | archive-date = August 31, 2015 }}</ref> It can take the form of over-reporting laudable behavior, or under-reporting undesirable behavior. This bias interferes with the interpretation of average tendencies as well as individual differences. The inclination represents a major issue with [[Self-report study|self-report]] questionnaires; of special concern are self-reports of abilities, [[Personality|personalities]], [[Human sexual activity|sexual behavior]], and [[Recreational drug use|drug use]].<ref name="SDRdef" />

====Selection bias====
{{main|Selection bias}}
[[File:Simple random sampling.PNG|thumb|[[Sampling (statistics)|Sampling]] is supposed to collect of a representative [[statistical sample|sample]] of a [[population (statistics)|population]].]]
Selection bias is the conscious or unconscious bias introduced into a study by the way individuals, groups or data are selected for analysis, if such a way means that true randomization is not achieved, thereby ensuring that the sample obtained is not representative of the population intended to be analyzed.<ref>[http://www.cancer.gov/dictionary?CdrID=44087 Dictionary of Cancer Terms → selection bias] {{Webarchive|url=https://web.archive.org/web/20140705015055/http://www.cancer.gov/dictionary?CdrID=44087 |date=2014-07-05 }}. Retrieved on September 23, 2009.</ref> This results in a sample that may be significantly different from the overall population.