Editing Blinded experiment (section)

=== Bias ===
A number of biases are present when a study is insufficiently blinded. Patient-reported outcomes can be different if the patient is not blinded to their treatment.<ref>{{cite journal |last1=Hróbjartsson |first1=A |last2=Emanuelsson |first2=F |last3=Skou Thomsen |first3=AS |last4=Hilden |first4=J |last5=Brorson |first5=S |title=Bias due to lack of patient blinding in clinical trials. A systematic review of trials randomizing patients to blind and nonblind sub-studies. |journal=International Journal of Epidemiology |date=August 2014 |volume=43 |issue=4 |pages=1272–83 |doi=10.1093/ije/dyu115 |pmid=24881045 |pmc=4258786 }}</ref> Likewise, failure to blind researchers results in [[observer bias]].<ref>{{cite journal |last1=Bello |first1=S |last2=Krogsbøll |first2=LT |last3=Gruber |first3=J |last4=Zhao |first4=ZJ |last5=Fischer |first5=D |last6=Hróbjartsson |first6=A |title=Lack of blinding of outcome assessors in animal model experiments implies risk of observer bias. |journal=Journal of Clinical Epidemiology |date=September 2014 |volume=67 |issue=9 |pages=973–83 |doi=10.1016/j.jclinepi.2014.04.008 |pmid=24972762 |doi-access=free }}</ref> Unblinded data analysts may favor an analysis that supports their existing beliefs ([[confirmation bias]]). These biases are typically the result of subconscious influences, and are present even when study participants believe they are not influenced by them.<ref name=Truth>{{cite journal |last1=MacCoun |first1=Robert |last2=Perlmutter |first2=Saul |title=Blind analysis: Hide results to seek the truth |journal=Nature |date=7 October 2015 |volume=526 |issue=7572 |pages=187–189 |doi=10.1038/526187a |pmid=26450040 |bibcode=2015Natur.526..187M |doi-access=free }}</ref>