Error Proofing

In Japanese, ‘Poka-Yoke (pronounced Po-kaa-Yo-kay), also known as mistake-proofing or fail-saving, is also called error-proofing. Previously, error-proofing was called fool proofing or idiot-proofing. Using any automated device or method to prevent an error or detect it as quickly as possible so we can correct it is considered error-proofing.

You can use a simple procedure, such as drawing the picture of the TV remote on the desk to remind everyone at home to always keep it in the same spot. Or you could have the washing machine turn ON only after the water has been turned on and the machine has been closed properly.

Why does error-proofing need to be done?

It is essential to make processes and devices error-proof when financial resources, general welfare (of the society), and human resources are at stake. This will prevent damage, non-uniformity, and waste due to human interference. The error-proofing technique must be cheap and detect or report the error as soon as possible.

When should you use error-proofing?

  1. When the outcome depends on someone’s skills and experience.
  2. Avoiding the customer from making an error that could result in a loss for himself and his business.
  3. If something that could be avoided earlier can lead to a bigger problem later, it is better to avoid it.
  4. It is better and cheaper to avoid an error than to correct it after the fact.
  5. The same person is not always available to complete the entire life cycle of a product when a large group of people are involved.

How can you check for errors?

  1. Create a flowchart of the process, describing every step and indicating clearly where human intervention occurs.
  2. Identify the potential errors and analyze their root causes to determine its origin or source.
  3. List all possible ways to prevent the potential errors.
    1. Eliminate the steps that cause the error.
    2. Consider replacing the current step with one that is more reliable.
    3. Instead of letting the user make an error, help them to do the right thing in a more convenient way.
    4. Encourage the use of sensors, warning light, buzzers, and proximity detectors
  4. If it’s impossible to avoid an error, then at least make it clear and notify immediately to allow for any corrective actions to be taken. By doing this, you minimize the impact of the mistake.
    1. Encourage the use of color-coding or graphics to detect errors.
  5. Use the best method or process to eliminate errors and choose it for every possible error.