Continuous improvement with poka yoke

Poka yoke was introduced by industrial engineer Shigeo Shingo. He has used this process as a way to reduce the number and severity of errors on the Toyota production line. Rather than simply responding to a mistake, the focus with poka yoke is to identify the cause. When the cause is identified, a change is made that makes it much more difficult or even impossible to make the mistake again.

Errors can occur during the development of a product, which must be corrected at a later stage. Whatever the cause, mistakes are a huge waste of time and resources. This is why the concept of poka yoke was developed way back in the 1960s. Poka yoke is a term in Japanese that translates to "make something error-proof".

Poka yoke in practise

A good example of a poka yoke design from the manufacturing industry is SIM card slots in mobile phones. These are designed in such a way that the user can only insert the SIM cards correctly. There is no chance for the user to make a mistake when inserting the SIM card into a mobile phone. This makes the design error-proof.

Poke yoke can help make the work area, or even the entire organization, more error-proof. First identify the process it will be used for. Take the time to learn as much as you can about the system. Then analyze the ways in which that process can fail. Choose the right poka yoke approach:

• Shut Out Type: Avoid making the mistake

• Attention Type: Notify immediately that a mistake has been made

Determine if one of the following options is appropriate to avoid the error in the future:

• Contact: Using a physical characteristic of a part as a way to detect errors. For example, consider size, weight, shape or another physical parameter.

• Constant number: Identify errors by counting to ensure a consistent number of actions are taken in each process.

• Order: Use a checklist to ensure that every action within the process has been completed.

Test the applied method and see if it can reduce or eliminate the number of errors in a specific process.

Train everyone working on this process to use the new poka yoke procedures. This is important to make the improvements more effective,

Poke yoke applied for software development

A thoughtful design is much better than a good error message, which prevents a problem from occurring in the first place. Modern users often suffer from information overload and cannot always see or read everything on the screen. As a tester you can suggest a poka yoke approach. In addition, consider how a mistake can be prevented rather than corrected. For example, build a function so that only the supported file types can be selected in a file uploader.

Another example is when searching for results in Google. When the user makes a typo, Google corrects it and displays the results with the corrected search term. It is still possible for the user to search based on the entered result.

Continuous improvement

One of the main advantages of poka yoke is that it is ideal for creating an environment of constant improvement. When errors are discovered, poka yoke is used to prevent the error from happening again in the future, or to run checks to discover the problem immediately. This helps ensure that the whole system runs smoothly and if something goes wrong, poka yoke is used again.

Rather than simply trying to tackle each error individually, poka yoke actually works to identify and address the root cause of all errors. In the long run, this leads to a much more efficient and error-free development process. It will also enable the discovery and prevention of small and minor errors, which may have simply gone unnoticed in the past. That's why poka yoke is so important.

Closing words

Agile requires a transparent and self-organizing culture that strives for continuous improvement and faster value creation. In order for agile to be successful in your organization, you will have to eliminate unnecessary waste in your organization. Agile in Focus wants to help your company or team with this. Contact us, we are here for you!