Process metrics need to lead to the most appropriate behaviors. Processes have variability and may or may not have specifications.
Performance measurements for processes need to provide direction to the most appropriate behaviors considering both process variability and any specification that may exist. The output of processes can have both common-cause variability and special-cause variability.
In process metric reporting, typical process variability is separated from unusual events or trends. Traditionally this separation is make using statistical process control (SPC) charts such as x-bar and R charts and p-charts. How a process is performing for an in-control process relative to specifications traditionally involves techniques such as process capability indices.
However, traditional control charting and process capability reporting have mathematical issues. An Integrated Enterprise Excellence (IEE) 30,000-foot-level reporting format addresses these issues. IEE 30,000-foot-level reporting provides both a process stability assessment and predictive statement for stable processes in one chart.
This article describes a methodology for tracking a single-process output response over time to determine process stability and then, if the process is stable, provide a prediction statement.
Enhanced Individuals Control Chart with Process Capability Statement Read More »
With a high-level process-output tracking at the 30,000-foot-level, there will be an infrequent subgrouping/sampling plan such that the typical variability from input variables that could affect the response will occur between these subgroupings. An infrequent subgrouping/sampling interval could be day, week, or month, where responses from differing people, departments, machines, and so forth would be captured within each subgroup. 30,000-foot-level charting does not offer timely identification of process changes but instead provides a high-level view of how the process is performing from a customer-of-the-process point of view.
Enhanced Approach for How to Show Process Improvement Read More »
P-charts are used in quality control to identify when special-cause or out-of-control conditions occur in timeseries data so that timely corrective actions can be taken to resolve problems. Sometimes data from a p-chart are used also to provide a process capability statement or non-conformance statement.
Attribute, pass/fail proportion data, can be monitored over time for stability and then, when a process is stable, provide a prediction statement. When a process has a recent region of stability, it can also be said to be predictable. When this occurs, we can use historical data to make a statement about what we might expect in the future, assuming things stay the same; e.g., the center line of the chart if no transformations are needed to create the 30,000-foot-level chart, and the subgroup sizes are approximately the same.
Enhanced Attribute Data Control Chart with Process Capability Statement Read More »
This article will build on the Shewhart1 and Deming2 special-cause and common-cause variability concepts as it relates to attribute count data that occur in subgroups.
Organizations need to be able to calculate process capability when there is no specification; however, the traditional process capability indices of Cp, Cpk, Ppk, and Ppk require a specification.
How to Calculate Process Capability when there is no Specification Read More »
An enhanced Statistical Process Control SPC p-chart approach provides in one chart both a process stability and capability assessment/statement. The Integrated Enterprise Excellence (IEE) enhanced SPC p-chart 30,000-foot-level measurement approach for non-conformance rate time-series tracking of data (i.e., from a high-level overall process output point of view) also provides a prediction statement when a process
Enhanced SPC P-chart can Include Capability Statement in One Chart Read More »
This process capability index explained posting addresses the indices Cp, Cpk, Pp, and Ppk. An enhanced reporting methodology is also described that provides many benefits over a traditional approach.
Process Capability Index Explained: A Better Way Read More »
Organizations need a meaningful process capability analysis report methodology. Traditional process capability indices reports, including Cp, Cpk, Pp, and Ppk, can be confusing and deceiving.
How to Create a Meaningful Process Capability Analysis Report Read More »
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 part quality and other assessments. Measurement Systems Analysis (MSA) and Gage R&R study (Repeatability and Reproducibility) are an integral part of the Lean Six Sigma Black Belt and Green Belt training. 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 achievement of the three Rs goal is process performance metrics; i.e., a process’ performance report-out should lead to the most appropriate action or non-action. This objective is not unlike an inspection gage MSA, which is to determine if inspectors can adequately determine whether a manufactured component should be accepted or rejected. Because of this performance-reporting need, it would seem that management and practitioners would be assessing how well current scorecard and metric reporting systems are doing from a MSA conceptual point of view. However, this does not seem to be occurring. The question is why do we not examine business metrics and process capability indices reporting from a MSA point of view with the same level of intensity that we do for product quality metrics? This one-hour Webinar will explain more on the magnitude of the issue: we’ll give focus to how Cp, Cpk, Pp, and Ppk process capability indices’ reporting is sensitive to how a given process is sampled; i.e., an MSA issue. A predictive metric reporting system will then be described for overcoming not only the issues of process capability indices but general business-performance scorecards.
Cp Cpk Pp Ppk Calculation and Understanding: A Webinar that Provides Important Details Read More »
