Thanks for your question.

The point of my post is that ideal quality, from a customer standpoint, is zero defects — nothing more. While you may not yet be able to achieve the ideal condition, it remains the ideal. A customer may tolerate less than that, but this a slippery slope. How do we rationalize the tradeoffs? Of course, in my example we are only talking about the quality of a dozen eggs. (Actually, to digress, a gentlemen from the U.K. responded to me a while back, “We don’t have cracked eggs in England.” I never verified that:)

But suppose we are talking about tradeoffs in an automobile. Consider the position taken by Ford in the mid-70′s regarding exploding gas tanks on its line of Pinto’s: “Ford found it cheaper to pay off the families of the victims of Pinto fires than the $137 million it would cost to fix the Pinto immediately, according to an internal Ford memo introduced during a civil trial. That meant it was not cost-effective to do the repairs.” http://www.autonews.com/article/20030616/SUB/306160770/lee-iacoccas-pinto:-a-fiery-failure#axzz2ecMEoG49

This idea of zero defects is not new, but it’s hard to ‘unlearn” the deep-seated AQL thinking that defects are unavoidable. This is one reason why so many organizations fail to gain the full benefits of TPS.

Bruce

I’m not sure I understand.

You have no doubt come up against the problem where aiming for zero defects becomes cost prohibitive. The customer simply won’t pay for the additional resources required for perfection.

In the case of eggs, I’d much rather quickly check for broken eggs than pay an extra $0.25 (to pull a number out of thin air) to be assured of perfection. No doubt the egg farmers know this, and thus have a tolerance level that achieves their goals.

I have dealt with this personally, where I am a manager of a greenhouse & nursery operation. Plants have an inherently high level of variation, and with over 1,000 varieties, grown in multiple sizes, and with quality standards changing through the season, combined with high turnover and seasonal staff who receive minimal training, the problem of picking orders first time with zero defects has thus far eluded us. When we tried to get the order picking perfect at the first stage, our productivity plummeted. When there was NO quality control at the first stage, productivity also plummeted (because it bogged down the upstream process with errors). We found that a moderate error rate was tolerable for the time being and has so far resulted in the highest productivity, because going too far either way destabilized the process.

In the meantime we’ve been working very hard at reducing the root causes of variation so that plants require less grading to begin with.

So, isn’t it okay to tolerate a certain level of defects if the cost of preventing them is greater than the value generated?

Love reading your posts, keep them coming!

Jason Rekker

St. Catharines, Ontario

________________________________