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''''{{Nihongo|Poka-yoke|ポカヨケ|}}''' {{IPA-ja|poka yoke|}} is a Japanese term that means "mistake-proofing". A poka-yoke is any mechanism in a [[lean manufacturing]] process that helps an equipment operator avoid (''yokeru'') mistakes (''poka''). Its purpose is to eliminate product defects by preventing, correcting, or drawing attention to human errors as they occur.<ref>{{cite web | title=Using Poka-Yoke Techniques for Early Defect Detection | url=http://facultyweb.berry.edu/jgrout/pokasoft.html | last= Robinson | first=Harry | year=1997 | accessdate=May 4, 2009}}</ref> The concept was formalised, and the term adopted, by [[Shigeo Shingo]] as part of the [[Toyota Production System]].<ref name=Shigeo /><ref>{{cite web | title=A Brief Tutorial on Mistake-proofing, Poka-Yoke, and ZQC | url=http://www.mistakeproofing.com/tutorial.html | author=John R. Grout, Brian T. Downs | accessdate=May 4, 2009 | publisher=MistakeProofing.com}}</ref> It was originally described as ''[[Baka (fool)|baka]]-yoke'', but as this means "fool-proofing" (or "[[Idiot proof|idiot-proofing]]") the name was changed to the milder ''poka-yoke''. More broadly, the term can refer to any [[behavior-shaping constraint]] designed into a process to prevent incorrect operation by the user.{{Citation needed|date=May 2009}} Similarly, a constraint that is part of the product (or service) design is considered [[Design for Manufacturability ]] or [[Design for X]]. A modern Poka-Yoke application is when a driver must press on the brake pedal (a process step, therefore a poka-yoke)) prior to starting an automobile. The interlock serves to prevent unintended movement of the car. An additional poka-yoke would be the switch in the car's gear shift that requires the car to be in Park or Neutral before the car can be started. These serve as behavior-shaping constraints as the sequence of "car in park (or neutral)" and/or "Foot on brake" must be performed before the car is allowed to start. Over time, the driver's behavior is conformed with the requirements by repetition and habit. ==History== The term poka-yoke was applied by [[Shigeo Shingo]] in the 1960s to industrial processes designed to prevent human errors.<ref>{{cite web | title=Using Poka-Yoke techniques for early defect detection | url=http://facultyweb.berry.edu/jgrout/pokasoft.html | author=H Robinson | accessdate=June 18, 2012}}</ref> Shingo redesigned a process in which factory workers, while assembling a small switch, would often forget to insert the required spring under one of the switch buttons. In the redesigned process, the worker would perform the task in two steps, first preparing the two required springs and placing them in a placeholder, then inserting the springs from the placeholder into the switch. When a spring remained in the placeholder, the workers knew that they had forgotten to insert it and could correct the mistake effortlessly. <ref>{{cite web | title= The Sayings of Shigeo Shingo: Key Strategies for Plant Improvement | url=http://www.qualitycoach.net/products/the-sayings-of-shigeo-shingo-key-strategies-f.asp | accessdate=August 20, 2012 | publisher=QualityCoach.Net }}</ref> Shingo distinguished between the concepts of inevitable human [[Error|mistake]]s and [[Product defect|defect]]s in the production. Defects occur when the mistakes are allowed to reach the customer. The aim of poka-yoke is to design the process so that mistakes can be detected and corrected immediately, eliminating defects at the source. == Implementation in manufacturing == Poka-yoke can be implemented at any step of a manufacturing process where something can go wrong or an error can be made.<ref name=qualityportal>{{cite web | url=http://thequalityportal.com/pokayoke.htm | title=Poka Yoke or Mistake Proofing :: Overview | publisher=The Quality Portal | accessdate=May 5, 2009}}</ref> For example, a [[jig (tool)|jig]] that holds pieces for processing might be modified to only allow pieces to be held in the correct orientation,<ref name="NKS">{{cite book |author = Nikkan Kogyo Shimbun |authorlink=Nikkan Kogyo Shimbun |title=Poka-yoke: improving product quality by preventing defects |publisher=Productivity Press |year=1988 |page=[http://books.google.com/books?id=hR_8Ulz6d_oC&pg=PA111 111] |isbn=978-0-915299-31-7}}</ref> or a digital counter might track the number of spot welds on each piece to ensure that the worker executes the correct number of welds.<ref name="NKS" /> Shigeo Shingo recognized three types of poka-yoke for detecting and preventing errors in a [[mass production]] system:<ref name=Shigeo>{{cite book | first1 = Shigeo | last1 = Shingo |authorlink=Shigeo Shingo | first2 = Andrew | last2 = Dillon |title=A study of the Toyota production system from an industrial engineering viewpoint |publisher = Productivity Press | location = Portland, OR |year=1989 |url =http://books.google.com/books?id=RKWU7WElJ7oC&pg=PA22 22 | isbn = 0-915299-17-8 |oclc=19740349}}</ref><ref name=qualityportal /> # The ''contact'' method identifies product defects by testing the product's shape, size, color, or other physical attributes. # The ''fixed-value'' (or ''constant number'') method alerts the operator if a certain number of movements are not made. # The ''motion-step'' (or ''sequence'') method determines whether the prescribed steps of the process have been followed. Either the operator is alerted when a mistake is about to be made, or the poka-yoke device actually prevents the mistake from being made. In Shingo's lexicon, the former implementation would be called a ''warning'' poka-yoke, while the latter would be referred to as a ''control'' poka-yoke.<ref name="Shigeo" /> Shingo argued that errors are inevitable in any [[manufacturing]] process, but that if appropriate poka-yokes are implemented, then mistakes can be caught quickly and prevented from resulting in defects. By eliminating defects at the source, the cost of mistakes within a company is reduced.{{cn|date = June 2013}} ==Implementation in service industries== Poka-yoke can also be implemented in service industries. [[Call center]]s have long had a challenge with compliance. Poor training, fatigue, forgetfulness, and the limits on human consistency all can lead to agents skipping key steps in the process. Disclosures are a good example: When a consumer makes a purchase of some kind, the call center agent is often required to provide the customer with key information. What the customer purchases dictates the disclosures that are required. It can be hard to train the agents in all the required combination of disclosures or the agents can sometimes forget to read the disclosures. Using [[agent-assisted automation]], the agents can provide the customers with all the required disclosures using pre-recorded audio files.<ref>Adsit, D. 2009 Mass Customization and the Transformation of the Call Center Industry http://www.kombea.com/RecentPress.htm</ref> By integrating the agent-assisted automation with the [[customer relationship management]] software, you can ensure that the agent cannot process/complete the order until the required disclosures are played. ssgsgsgsfgswfswfwasfewsaefwafwafwafawfv ==References== {{Reflist}} ==Further reading== * {{cite book |first=Shigeo |last=Shingo |authorlink=Shigeo Shingo |title=Zero quality control: source inspection and the poka-yoke system |publisher=Productivity Press |location=[[Portland, Oregon]] |year=1986 |pages= |isbn=0-915299-07-0 |oclc=13457086 |url=http://books.google.com/?id=gkE8K7axQbYC |accessdate=30 April 2009}} * {{cite book |author=[[Nikkan Kogyo Shimbun]] |title=Poka-yoke: improving product quality by preventing defects |publisher=Productivity Press |location=[[Portland, Oregon]] |year=1988 |pages= |isbn=0-915299-31-3 |oclc=300302752}} * {{cite journal |first=C. M. |last=Hinckley |coauthors=P. Barkan |year=1995 |title=The role of variation, mistakes, and complexity in producing nonconformities |journal=Journal of Quality Technology |volume=27 |issue=3 |pages=242–249 |url=http://www.asq.org/qic/display-item/index.html?item=11413}} ==External links== *[http://www.shmula.com/1993/everyday-poka-yoke-preventing-theft Poka-Yoke Example] Written by Shmula *[http://pokayoke.wikispaces.com Mistake-Proofing Example Wiki] [[Category:Japanese business terms]] [[Category:Lean concepts]]'