ASQ - Energy and Environmental Division

In the simplest terms, process control refers to "how you do what you say you do." Process control can range from simple "to-do" lists to extravagant quantitative initiatives incorporating Six Sigma statistical controls, continual measurement and improvement, and scientific algorithms.

I propose a qualitative approach to complement and accentuate these efforts. Qualitative process control focuses on determining the composition of a process, as contrasted with statistical process control, which addresses the numerical values or quantities of each part of the process. This qualitative approach is versatile and can be applied to different types of management systems. Effective qualitative process control demonstrates where value is added and where risks are controlled.

Adding value
Value is added through the interactions of raw materials, human resources, tools and equipment, capital assets, and other related entities. A qualitative process description indicates how these interactions occur and identifies the specific entities involved.

Value can also be added as items move from raw materials through works in progress and finally to finished goods. A qualitative process description indicates the specific steps where these transitions occur.

Controlling risks
For every risk, there is a level of tolerance. A qualitative approach identifies risks and the corresponding levels of tolerance for each risk. In determining risk tolerances, you can consult customers, industry associations, and regulatory bodies. It’s essential to understand the level of risk tolerance so that risks can be properly addressed.

When employing qualitative process control, you’ll want to consider contributing factors to the process, including the design, the components or materials, the interactions, and the activities of the process itself. Each of these contributing factors possesses inherent risks, which must be identified, evaluated, and addressed in a manner reflecting its severity and frequency of occurrence.

At specific points in the process, or control points, you’ll monitor, verify, or validate to control for identified risks and to ensure a positive and desirable outcome. Monitoring is real-time activities that are conducted to continually evaluate items and look for indications of deficiencies or malfunctions. Verification is the off-line examination of an item against predetermined criteria. Validation ensures that items are fit for use and acceptable for release. Effective use of process control points determines the extent to which risks have been addressed.

When you identify a risk at a control point, you’ll plan a strategy to lower that risk. Your choice of action can range from immediate responses to troubleshooting and root-cause analysis to long-term corrective action. Immediate responses are preplanned and approved to address known and easily correctable situations (e.g., if X occurs, then perform Y to resolve). Troubleshooting requires off-line intervention to provide a short-term fix for the condition, and these activities should be documented for future reference. Root-cause analysis examines the risks and endeavors to determine the underlying problem. Finally, long-term corrective action is a comprehensive approach that addresses the risks, the root cause, the correction, the verification of corrections, and the ongoing modification of the process to prevent recurrence.

The use of qualitative process control clarifies existing processes by delineating entities and their interactions. This approach will reinforce the need for process controls and identify areas for process improvement, resulting in a management system that adds value and controls risks.

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