Enhanced Process Capability Analysis Report

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An enhanced process capability report is needed in organizations. Traditional process capability indices including Cp, Cpk, Pp, and Ppk can be confusing and deceiving.

process capability analysis report can be very confusing

The process capability analysis report linked-to PDF highlights issues with traditional process capability indices reporting and what can be done to resolve the problem. The Integrated Enterprise Excellence (IEE) business management system for 30,000-foot-level predictive performance reporting  is the approach that is described in the article, which provides needed traditional process capability reporting enhancements.

Process capability and process performance report-outs should lead to the most appropriate action or inaction, which is independent of the person compiling the information.   However, this does not often occur with traditional techniques as described in a published article (PDF below) ″Insight Or Folly? Resolve Issues With Process Capability Indices, Business Metrics″, written by Forrest Breyfogle .

Consider the different approaches someone might use to report the output of a process. One might choose a bar chart, a pie chart, a red-yellow-green scorecard, a table of numbers, or process capability indexes (that is, Cp, Cpk, Pp, Ppk, and Cpm).

For a given situation, each of these reporting methods can provide a very different, and somewhat subjective, picture of how a process performs and whether any actions should be taken or not.

The PDF article below gives focus to an enhanced method that addresses traditional process capability indices reporting disputes.

Process Capability Analysis Example: Process Capability Standard Deviation Calculation

To illustrate the magnitude of the process performance and process capability reporting issue, the PDF article below will use a process capability analysis example to illustrate how reporting Cp, Cpk, Pp, and Ppk process indices values can be very sensitive to process sampling procedures – a conceptual Measurement Systems Analysis (MS) issue.

Process capability indices is basically the reporting of a customer specification need by the variability of the process, which is a multiple of the processes’ standard deviation. However, from the chart above, one can see how an inputted standard deviation value from a process control chart to this formula could differ a lot dependent upon the sampling procedure from a process (PDF article provides more details).


In addition, traditional process capability indices reporting describe historically what happened, which may not be representative of the future. What is really desired is a statement about what is expected in the future so changes can be made, if needed.

In Lean Six Sigma, much training effort is spent on conveying the importance of having a measurement system so that consistent and correct decisions are made relative to assessing part quality and process attributes.  In this training, Measurement Systems Analysis (MSA) and associated Gage R&R (Repeatability and Reproducibility) studies are an integral part of this overall focus.

It would seem that conceptually MSA should be a reporting consideration for all forms of measurements, including business performance metrics. In addition, one would think that focus should be given so that metric statements are in clear understandable language. But, in the real world, how well are these attributes achieved? Often not as good as one might think.  An improved methodology is described in this PDF’s Process Capability Analysis Example.

Process Capability Analysis Example: Achieving the 3R’s of Business

It should be the goal of every organization to achieve the three Rs of business; i.e., everyone doing the Right things, and doing them Right, at the Right time.  One tool that provides direction for the three Rs achievement goal is process performance metrics; i.e., a process performance report-out should lead to the most appropriate action or non-action, which is independent of the person compiling the information.

This basic right-behavior objective is not unlike an inspection gage MSA, which insures that inspectors can adequately determine whether a manufactured component should be accepted or rejected.  The PDF’s process capability analysis example shows how this can be achieved.

For more information about the above described process capability analysis example methodology, download the published ASQ Quality Progress January 2010 PDF article titled ″ Insight Or Folly? Resolve Issues with Process Capability Indices, Business Metrics” written by Forrest Breyfogle.


Contact Us to set up a time to discuss with Forrest Breyfogle how your organization could gain much from an IEE predictive reporting alternative to traditional process capability indices reporting for your data.