Mistakes happen. It’s one of the most basic truths of life, along with the idea that perfection is a myth. And while society has largely accepted both of these truths, it hasn’t stopped people from looking for ways to edge us closer to error-free, or perfection. Mistake Proofing, or error proofing, also known as Poka-Yoke, is defined as the process of applying a particular set of techniques to prevent and/or detect errors as early in a process as possible.
Three Types of Mistake-Proofing
While it may seem like the goal is to create mistake-proofing techniques that help prevent all errors, that’s not realistic. Having a combination of the three mistake-proofing techniques is the most effective as it provides the most mistake-proofing coverage.
Prevention is the top priority for all mistake-proofing techniques. A treadmill kill switch that attaches to the runner is a great example of ‘prevention’ mistake-proofing. If something happens to the runner, the kill switch will automatically shut down the machine, preventing potential injury.
Because not all errors are preventable, mistake-proofing techniques that help detect errors early in a process are crucial. A tire pressure light in a car is an excellent example of ‘detection’ mistake-proofing. While several ‘prevention’ mistake-proofing techniques are implemented into a car’s tires, they can’t prevent all causes of lost air pressure. The air pressure gauge tells the operator to get air before further damage occurs.
Mistakes are inevitable. Prevention techniques can’t predict every anomaly, and detection techniques are essential for setting off the alarm bells. So, when a mistake does happen, having a reduction strategy at the ready can be sometimes life-saving. An indoor sprinkler system, for example, is a fantastic reduction technique aimed at reducing the impact of a building fire.
Three Process Placements for Mistake-Proofing
After the Process
A common place for mistake-proofing techniques to exist is at a pre-determined inspection point during the production process. On a car production line, for example, there might be inspection points after various pieces of the car are built. Someone must evaluate the car part, ensure its quality passes a written set of standards, then decide to move it through to the next step or stop the process altogether. This enables the detection of product defects before it moves into another step of the process and causes future problems.
While this is a robust method, it’s not the most effective.
During the Process
A mistake-proofing technique that occurs during the process coincides with detection. Essentially, this technique acts as a fire alarm, warning the operator or machine that an error has occurred. This enables the operator to identify precisely where the mistake took place and make any necessary adjustments before the part or product continues through the process.
Before the Process
The best place for mistake-proofing, however, is before the process begins. This means that a certain set of standards or conditions must be met before the machine or operator takes the first step in the process.