The Next Leap in Productivity: What Top Managers Really Need to Know about Information Technology

4.13. Deming's Error Prevention Concept

Deming taught that fixing problems where they occur in the manufacturing process not only eliminates many quality problems in the finished product, but also promotes the ultimate goal of process improvement. He found that by fixing the process itself, it was possible to prevent the same types of errors from reoccurring.

Deming advocated process improvement through a root cause analysis and prevention. The basic procedure for implementing Deming's process quality improvements is as follows:

1. Identify a defect.

2. Find the root cause of the defect.

3. Locate the point in the production line that caused the defect.

4. Implement preventative practices to ensure that similar defects do not reoccur.

5. Monitor the process to verify effectiveness of the preventative practices.

For example, say inspectors on an auto assembly line discover that seat bolts are loose. The cause of this defect is that the bolts do not exactly fit the tool used to tighten them. They locate the point in the assembly line where the bolts are being tightened, and apply a corrective action by providing a tool that fits properly. Monitoring the process is accomplished by closely inspecting the seat bolts for tightness and collecting the data about the amount of time saved by using the right tool.

Once you grasp these concepts, they seem obvious. But you may be surprised to learn that they are not universally adopted in software development. In the software industry, postproduction testing ...