Poka-yoke (ポカヨケ) [poka yo-ke] is a Japanese term that means "fail-safing" or "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.[1] The concept was formalised, and the term adopted, by Shigeo Shingo as part of the Toyota Production System.[2][3] It was originally described as baka-yoke, but as this means "fool-proofing" (or "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. Similarly, a constraint that is part of the product (or service) design is considered DFM or DFX.
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Poka-yoke can be implemented at any step of a manufacturing process where something can go wrong or an error can be made.[4] For example, a jig that holds pieces for processing might be modified to only allow pieces to be held in the correct orientation,[5] 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.[6]
Shigeo Shingo recognized three types of poka-yoke for detecting and preventing errors in a mass production system:[2][4]
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.[7]
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.[8]
Poka yoke system is generally known as PKS.
Poka-yoke can also be implemented in service industries. Call Centers 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.[9] 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.