Editing Sunk cost (section)

=== Plan continuation bias ===
A related phenomenon is plan continuation bias,<ref name=Squair2011>{{Cite web|url=https://criticaluncertainties.com/2011/06/26/flying-in-the-rear-view-mirror/|archive-url=https://web.archive.org/web/20150623002211/http://criticaluncertainties.com/2011/06/26/flying-in-the-rear-view-mirror/|url-status=usurped|archive-date=June 23, 2015|title=Flying in the rear view mirror|date=2011-06-26| website=Critical Uncertainties|language=en|access-date=2019-12-28}}</ref><ref>{{Cite web|url=https://safetyrisk.net/safety-and-the-sunk-cost-fallacy/|title=Safety and The Sunk Cost Fallacy|date=2015-06-20|website=SafetyRisk.net|language=en-US|access-date=2019-12-28}}</ref><ref>{{Cite web|url=https://www.thehumandiver.com/blog/17-cognitive-biases|title=17 Cognitive Biases which Contribute to Diving Accidents|website=www.thehumandiver.com|language=en|access-date=2019-12-28}}</ref><ref>{{Cite journal|last1=Winter|first1=Scott R.|last2=Rice|first2=Stephen|last3=Capps|first3=John|last4=Trombley|first4=Justin|last5=Milner|first5=Mattie N.|last6=Anania|first6=Emily C.|last7=Walters|first7=Nathan W.|last8=Baugh|first8=Bradley S.|date=2020-03-01|title=An analysis of a pilot's adherence to their personal weather minimums|journal=Safety Science|volume=123|pages=104576|doi=10.1016/j.ssci.2019.104576|s2cid=212959377 |issn=0925-7535}}</ref><ref>{{Cite web|url=https://www.faa.gov/news/safety_briefing/2018/media/JulAug2018.pdf|title=FAA Safety Briefing – July August 2018|website=FAA}}</ref> which is recognised as a subtle [[cognitive bias]] that tends to force the continuation of a plan or course of action even in the face of changing conditions. In the field of aerospace it has been recognised as a significant causal factor in accidents, with a 2004 NASA study finding that in 9 out of the 19 accidents studied, aircrew exhibited this behavioural bias.<ref name=Squair2011 />

This is a hazard for [[Sea captain|ships' captains]] or [[aircraft pilot]]s who may stick to a planned course even when it is leading to fatal disaster and they should abort instead. A famous example is the [[Torrey Canyon oil spill]] in which a [[SS Torrey Canyon|tanker]] ran aground when its captain persisted with a risky course rather than accepting a delay.<ref name="FT">{{citation |first=Tim |last=Harford |author-link=Tim Harford |date=18 January 2019 |url=https://www.ft.com/content/9e31e990-1a6a-11e9-b93e-f4351a53f1c3 |archive-url=https://ghostarchive.org/archive/20221210/https://www.ft.com/content/9e31e990-1a6a-11e9-b93e-f4351a53f1c3 |archive-date=2022-12-10 |url-access=subscription |url-status=live |title=Brexit lessons from the wreck of the Torrey Canyon |newspaper=Financial Times}}</ref> It has been a factor in numerous air crashes and an analysis of 279 approach and landing accidents (ALAs) found that it was the fourth most common cause, occurring in 11% of cases.<ref name="FSD">{{citation |first1=Ratan |last1=Khatwa |first2=Robert |last2=Helmreich |date=November 1998 – February 1999 |url=https://flightsafety.org/fsd/fsd_nov-feb99.pdf |title=Analysis of Critical Factors During Approach and Landing in Accidents and Normal Flight |magazine=Flight Safety Digest |pages=1–77}}</ref> Another analysis of 76 accidents found that it was a contributory factor in 42% of cases.<ref name="ASW">{{citation |first1=Benjamin A. |last1=Bermin |first2=R. Key |last2=Dismukes |url=https://flightsafety.org/wp-content/uploads/2009/07/asw_dec06.pdf |title=Pressing the Approach |magazine=Aviation Safety World |pages=28–33 |date=December 2006}}</ref>

There are also two predominant factors that characterise the bias. The first is an overly [[optimism|optimistic]] estimate of probability of success, possibly to reduce [[cognitive dissonance]] having made a decision. The second is that of personal responsibility: when you are personally accountable, it is difficult for you to admit that you were wrong.<ref name=Squair2011 />

Projects often suffer [[cost overrun]]s and delays due to the [[planning fallacy]] and related factors including excessive optimism, an [[unwillingness to admit failure]], [[groupthink]] and [[Loss aversion|aversion to loss]] of sunk costs.<ref name="BIT">{{cite news |author=Behavioural Insights Team |date=July 2017 |url=https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/627790/lit-review-exploration-of-behavioural-biases.pdf |title=A review of optimism bias, planning fallacy, sunk cost bias and groupthink in project delivery and organisational decision making |work=An Exploration of Behavioural Biases in Project Delivery at the Department for Transport |publisher=[[GOV.UK]]}}</ref>