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Poka-yoke
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Poka-yoke
Poka-yoke (ポカヨケ; [poka joke]) is any mechanism in a process that helps an equipment operator to avoid mistakes and defects by preventing, correcting, or drawing attention to human errors as they occur. It is a Japanese term that means "mistake-proofing" or "error prevention", and is also sometimes referred to as a forcing function or a behavior-shaping constraint.
The concept was formalized, and the term adopted, by Shigeo Shingo as part of the Toyota Production System.
Poka-yoke was originally baka-yoke, but as this means "fool-proofing" (or "idiot-proofing") the name was changed to the milder poka-yoke. Poka-yoke is derived from poka o yokeru (ポカを避ける), a term in shogi that means avoiding an unthinkably bad move.
More broadly, the term can refer to any behavior-shaping constraint designed into a process to prevent incorrect operation by the user.
A simple poka-yoke example is demonstrated when a driver of the car equipped with a manual gearbox must press on the clutch pedal (a process step, therefore a poka-yoke) prior to starting an automobile. The interlock serves to prevent unintended movement of the car. Another example of poka-yoke would be the car equipped with an automatic transmission, which has a switch that requires the car to be in "Park" or "Neutral" before the car can be started (some automatic transmissions require the brake pedal to be depressed as well). These serve as behavior-shaping constraints as the action of "car in Park (or Neutral)" or "foot depressing the clutch/brake pedal" must be performed before the car is allowed to start. The requirement of a depressed brake pedal to shift most of the cars with an automatic transmission from "Park" to any other gear is yet another example of a poka-yoke application. Over time, the driver's behavior is conformed with the requirements by repetition and habit.
When automobiles first started shipping with on-board GPS systems, it was not uncommon to use a forcing function which prevented the user from interacting with the GPS (such as entering in a destination) while the car was in motion. This ensures that the driver's attention is not distracted by the GPS. However, many drivers found this feature irksome, and the forcing function has largely been abandoned. This reinforces the idea that forcing functions are not always the best approach to shaping behavior.
The microwave oven provides another example of a forcing function. In all modern microwave ovens, it is impossible to start the microwave while the door is still open. Likewise, the microwave will shut off automatically if the door is opened by the user. By forcing the user to close the microwave door while it is in use, it becomes impossible for the user to err by leaving the door open. Forcing functions are very effective in safety critical situations such as this, but can cause confusion in more complex systems that do not inform the user of the error that has been made.
These forcing functions are being used in the service industry as well. Call centers concerned with credit card fraud and friendly fraud are using agent-assisted automation to prevent the agent from seeing or hearing the credit card information so that it cannot be stolen. The customer punches the information into their phone keypad, the tones are masked to the agent and are not visible in the customer relationship management software.
Hub AI
Poka-yoke AI simulator
(@Poka-yoke_simulator)
Poka-yoke
Poka-yoke (ポカヨケ; [poka joke]) is any mechanism in a process that helps an equipment operator to avoid mistakes and defects by preventing, correcting, or drawing attention to human errors as they occur. It is a Japanese term that means "mistake-proofing" or "error prevention", and is also sometimes referred to as a forcing function or a behavior-shaping constraint.
The concept was formalized, and the term adopted, by Shigeo Shingo as part of the Toyota Production System.
Poka-yoke was originally baka-yoke, but as this means "fool-proofing" (or "idiot-proofing") the name was changed to the milder poka-yoke. Poka-yoke is derived from poka o yokeru (ポカを避ける), a term in shogi that means avoiding an unthinkably bad move.
More broadly, the term can refer to any behavior-shaping constraint designed into a process to prevent incorrect operation by the user.
A simple poka-yoke example is demonstrated when a driver of the car equipped with a manual gearbox must press on the clutch pedal (a process step, therefore a poka-yoke) prior to starting an automobile. The interlock serves to prevent unintended movement of the car. Another example of poka-yoke would be the car equipped with an automatic transmission, which has a switch that requires the car to be in "Park" or "Neutral" before the car can be started (some automatic transmissions require the brake pedal to be depressed as well). These serve as behavior-shaping constraints as the action of "car in Park (or Neutral)" or "foot depressing the clutch/brake pedal" must be performed before the car is allowed to start. The requirement of a depressed brake pedal to shift most of the cars with an automatic transmission from "Park" to any other gear is yet another example of a poka-yoke application. Over time, the driver's behavior is conformed with the requirements by repetition and habit.
When automobiles first started shipping with on-board GPS systems, it was not uncommon to use a forcing function which prevented the user from interacting with the GPS (such as entering in a destination) while the car was in motion. This ensures that the driver's attention is not distracted by the GPS. However, many drivers found this feature irksome, and the forcing function has largely been abandoned. This reinforces the idea that forcing functions are not always the best approach to shaping behavior.
The microwave oven provides another example of a forcing function. In all modern microwave ovens, it is impossible to start the microwave while the door is still open. Likewise, the microwave will shut off automatically if the door is opened by the user. By forcing the user to close the microwave door while it is in use, it becomes impossible for the user to err by leaving the door open. Forcing functions are very effective in safety critical situations such as this, but can cause confusion in more complex systems that do not inform the user of the error that has been made.
These forcing functions are being used in the service industry as well. Call centers concerned with credit card fraud and friendly fraud are using agent-assisted automation to prevent the agent from seeing or hearing the credit card information so that it cannot be stolen. The customer punches the information into their phone keypad, the tones are masked to the agent and are not visible in the customer relationship management software.