The question is, how might we best go about designing these fail-safes?
To begin, poka-yokes must be devised to prevent a particular type of error, which is why it is so important to thoroughly study the problem, the process, and the root causes. Once you have all the facts and data about what is going wrong most often, in what way, and why, you can set your collective creative minds to designing a poka-yoke that most effectively and efficiently prevents the most frequent human errors or omissions.
Yet a simple and powerful poka-yoke is almost never the first solution a team comes up with.
The best ideas take creativity, collaboration, and the time to press on past the weaker solutions that come to mind first. Most often, the first idea ― which, as noted above, almost never represents the best solution ― is one of the following:
- Ask people to be more careful
- Ask management to send an email telling people to be more careful
- Schedule a training session in which people are instructed to, yes, be more careful
These solutions might help for a little while, but improvement is fleeting.
Instead, armed with a thorough understanding of the process and how things go wrong, you must keep brainstorming ideas until you can find a way to inexpensively make it much easier to do the work right or at least automatically alert a person when he or she has just made the mistake.
In addition, people often progress through weaker controls to progressively more effective poka-yokes. For example, one garage progressed from a weak control ― a warning sign stating ‘No vehicles higher over 7 feet high’ ― to a bar at 7 feet, which when pressed set off flashing lights and warning sounds. Eventually, they had an inexpensive laser beam which when broken would trigger an arm to fall, blocking entry. No more difficult extraction of vehicles that exceeded the height limit!