How do you achieve quality ?

Last week, in the train, I meet a friend. He’s team leader and was upset by the evolution of the process he’s working in. He explains to me than now more and more the people working in his team are less interested in quality. Since 5 years, his team is divided in two : doers and checkers. The checkers, the most experienced people, are assuring quality by inspection. Before the doers (the juniors) and checkers were doing the same job but had a clear purpose: “design quality into the services” rather than inspect it.
He’s not the only one to be upset, W Edwards Deming would also be. The third of the 14 points of W Edwards Deming for the transformation of management suggests that inspection is too late: "Cease reliance on mass inspection to achieve quality. Eliminate the need for inspection on a mass basis by building quality into the product in the first place."

Today, like my friend in the train, a lot of people are working in processes organized around mass inspection. At the end of a process, dedicated full-time collaborators inspect 100% of these products/services, we called them the checker. The ratio of checker/maker is even sometimes of 100%. Those checkers validate the good and ask the doers to rework for the bad. Because full-time checkers control the service, the Management Thinking behind is “the customer is receiving a good service”.

I also see many problems with that thinking. I would only illustrate two.

- It’s expensive. How many resources, time and money dedicates the company to control and to produce products that have to be “reworked” ?
- Don’t we waste our people potential by using mass inspection? Is it not better to use our most experienced resources to build quality in the process instead to control the quality?

Checkers have not to be responsible for the quality of the output but should be responsible to put quality in the process, to produce quality, first time right. Too much reliance on inspection also supports a "blame the maker" mentality.

I don’t mean the goal is to remove all inspection. I don’t mean the goal is to remove all checkers. I mean the purpose of inspection need to be redefined to produce the right things right. Inspection is useful as a means to learn and to drive further quality improvement efforts, rather than looking for a culprit to blame. When organizations work to improve processes and systems, risks, defects are systematically reduced.

The purpose of a control chart is not to monitor

 Shewhart has invented the tool called process behavior chart or control chart to provide guidance for improvement.

Control chart helps us to understand the difference between common and special causes.

A common-cause variation is a routine variation. If the data’s are within the limits, the process displays nothing except “routine variation”. Shewhart called a process that features only common-cause variation as being in statistical control The process is stable and predictable.

Special-cause variation always arrives as a surprise. It is the signal within a system. For example, when a points fall outside the limits of a process behavior chart , it’s a signal of exceptional variation. So you try to identify the causes of the exceptional variation.

We’ve all learned that the first mistake in interpreting data is to interpret noise as it were a signal, the second mistake in interpreting data is to fail to detect a signal when it is present.

But most often when we have only common-causes, we look at the process and we think it’s working well. So, things are maintaining as they are. By maintaining things as they are, we don’t improve. Common-causes doesn’t mean that we’re doing the right things right.

The discovery of two types of variation is the first step toward the Deming Management Theory, but most often we use control chart for monitoring purpose not for improvement purpose. If we are just using the control chart to monitor our process, we’re forgetting the major objectives of the tool and the philosophy behind.

As expressed by Wheeler, in his book understanding variation, the question is not whether or not the techniques will work – but rather whether or not you will make them work. Those who don’t use process behavior charts have no advantages over those who can’t.

Source : Wheeler, understanding variation, the key to Managing chaos…