What is Error Proofing?

Error proofing

Error proofing or mistake proofing or fail-safing is also called as ‘Poka-Yoke’ (pronounced as Po-kaa-Yo-kay) in Japanese. Error proofing was previously called fool-proofing or idiot proofing. Error proofing involves the use of any automatic device or method that makes it impossible to make an error or at-least detect it as soon as possible in order to correct it.

It can be as simple process to draw a picture of a TV remote on the table and hence help everybody at home in reminding to keep the remote in the same place every time or a washing machine not turning ON till the water is turned on and machine is shut properly.

Why is error proofing required?

When there are resources involved, money involved, and general wellbeing (of society at-large) involved, it becomes necessary making processes or devices mistake proof to avoid damage, non-uniformity, rework, and wastage due to human intervention. It only requires that the error proofing method has to be inexpensive, it has to surely detect the error or report it at the earliest.

When do you use error proofing?

1. When human errors cause mistakes or defects and the output depends on somebody’s skill and experience.
2. To avoid customer making error and making a loss to himself and the business.
3. When something can be avoided in earlier stages that can cause bigger problem in later stages.
4. When any error becomes too costly to rectify and it is cheaper and better to prevent its occurrence in the first place.
5. When a large number of people are involved in a process or producing an output and the same person may not be available throughout the life cycle of the product.

How do you error proof?

1. Create a flow chart of the process describing each step and clearly mentioning where the human interventions occur.
2. Identify each potential error and try to do a root cause analysis to find its source or origin.
3. For each potential error, list down potential ways of making it impossible to make the error.
   1. Think of eliminating the step that causes the error.
   2. Think of changing he step with a better, failsafe step.
   3. Think of helping the user to exercise the correct step in an easier way instead of making an error.
   4. Encourage the usage of sensors, warning lights, buzzers, proximity detectors etc
4. In any case if it is impossible to avoid the error at-least try to make it obvious and reported immediately so that any necessary corrective action can be taken. Thereby you are minimizing the effects of the error.
   1. To detect errors, encourage usage of color coding or graphics, checking for completeness, templates etc
5. Choose the best process or device or method to error proof and use it for each potential error.

Error proofing performance window

It is generally suggested to allow one month for observation and recording the errors and their error proofing data.