His Point #5 is "Improve Constantly and Forever the System of Production and Service."
Not only must quality be built into products and services at the design stage, but efforts at quality improvement must be pursued constantly. Points 3 and 4 taught us that defects caught at the inspection stage (say, just before shipping the product to the customer) do nothing to improve the process, and therefore ensure better quality going forward. In fact, catching defects at the end of the line is characterized by Dr. Deming as "fire fighting", a term with which I am sure we are all too familiar. He uses the following analogy:
"You are in a hotel. You hear someone yell fire. He runs for the fire extinguisher and pulls the alarm to call for the fire department. We all get out. Extinguishing the fire does not improve the hotel. That is not improvement of quality. That is putting out fires."
Catching defects at the point of outbound shipping, for example, is too late. Cost has been built in to the product or service by this stage, and frequently the cause of such defects may be very difficult to find. I am reminded of the years that I worked for a famous manufacturer of high-quality crystal stemware and decor. We would, as a matter of routine, inspect every piece of product prior to final shipment. Fair enough. We did this as a service to our customers, to make absolutely sure that each customer was receiving virtually perfect product. We did, only occasionally, find defects, such as small bubbles within the glass or tiny scratches on the surface. Further, we did experience some small level of customer returns due to defects that they found or perceived. It broke my heart every time we found a defect at either of these two stages. This product had been designed by skilled artists. It had been created from shards of leaded crystal by skilled glass blowers and cutters. It had been carefully cleaned, wrapped and packaged to withstand shipping and travel from Europe to Canada. It had been handled, counted and stored with great care while in the Canadian warehouse, which I managed. So much love, and care, and cost had been built in to that piece of crystal, only to have it rejected and destroyed at the final step. What a shame.
But there are two points that I learned: one was that the pursuit of the holy grail of "zero defects" is folly. As a goal, it makes no sense. Focus on the method, as Dr. Deming advises. The second is that by focus upon the method, by building the skill set of its workers, artisans, and involving and encouraging employees from all functional areas (from purchasing to engineering to finance to logistics to sales) in the total quality culture, this company was able to build and maintain a reputation for its brand that was beyond compare.
It can be done!