Situations in Which Poka Yoke Works Well

Poka yoke should not be approached as a panacea for all kinds of mistakes. It is important to understand that poka yoke may be more suitable in certain situations than others. Grout provides guidelines for situations where it works well and where it does not (see Table 9.1).^[9]

Table 9.1. Applicability of Poka Yoke

Works Well

Does Not Work Well

In manual operations where worker vigilance is needed Where mispositioning can occur Where adjustment is required Where teams need commonsense tools and not another buzzword Where SQC is difficult to apply or apparently ineffective Where attributes, not measurements, are important Where training costs and employee turnover are high Where mixed-model production occurs Where customers make mistakes and blame the service provider Where special causes can reoccur Where external failure costs dramatically exceed internal failure costs Where product nonfunction can be catastrophic

Where destructive tests are used Where the production rate is very rapid Where shifts occur more rapidly than they can be responded to Where control charts are used effectively for successive and self-checks only

Poka yoke can be very effective in software development processes. Its applicability is supported by the various considerations listed in Table 9.1. People affected by the process must be involved in designing a poka yoke system. Such systems should be simple and free of complexity (itself a cause of defects). Simple, commonsense tools work best. But poka yoke is not rocket science, nor is it a silver bullet, so it should not be approached as such.