The 5 principles that shaped the quality movement can help frame our responses to the supply chain security challenge.

1.  Quality assurance through final product inspection is the last resort. Inspection does not improve quality. Screening is expensive, and it is susceptible to two kinds of statistical errors known as Type I (labeling a conforming item as nonconforming) and Type II (missing a nonconforming item).

2.  Assuring that the process is functioning in an in-control state is preferable to final product inspection. A process that is out-of-control will produce many more nonconforming items. Detecting the out-of-control state, identifying the causes, and restoring the process to an in-control state in a timely fashion will always improve quality.

3.  Quality assurance requires total organizational focus. Everyone should be aware of the quality imperative. Quality is not just the responsibility of the quality control department or quality inspectors.

4.  Prevention is always the preferred strategy. Companies should strive to install processes that ensure nonconforming items cannot be made or, if they are made, that can immediately identify and correct them before they turn into defects.

5.  Quality should be designed in. Products need to be designed so that they are less likely to be produced with defects. Processes must be designed so that the process variation is at a minimum.