iSixSigma

Measurement Systems Analysis (MSA)/Gage R&R

Case Study: Use Category Resolution to Assess Gage R&R Results

Although the gage reproducibility and repeatability (GR&R) study is a crucial tool in Six Sigma’s DMAIC (Define, Measure, Analyze, Improve, Control) toolset, it is not the most glamorous; mistakes in its execution are common among new Six Sigma practitioners. The standard for assessing if a gage is acceptable can vary significantly from organization to organization,…

2 comments

MSA: Be Sure that Your Data Is Valid

When I was trained as a Green and Black Belt, I didn’t fully understand the value of measurement system analysis (MSA). The concept worked, but I thought it was something that you do in one project out of 10 – only when you have the obvious opportunity to prepare a study with the possibility to…

6 comments

Avoid Two Common Mistakes in Measurement System Analysis

Measurement system analysis (MSA) determines whether the measurement system is adequate and confirms that significant error is not introduced to the true value of a process characteristic. MSA is the one of the most misunderstood and underused concepts in Six Sigma. This article highlights two of the common mistakes made during the study and explains…

4 comments

Understand the Difference Between Verification and Validation

Many people use the terms verification and validation interchangeably without realizing the difference between the two. Not understanding that difference can lead to many models that do not truly represent a real-world process and lead to errors in forecasting or predicting of the outcomes. In this article, we will explore the meaning, importance, differences and…

6 comments

A Comparison of Measurement System Analysis Metrics: Part 2 of 2

The precision of a measurement system is commonly assessed using a gage repeatability and reproducibility (GR&R) study.  Part 1 of this article discussed metrics used in measurement system analysis. Here, Part 2 compares commonly used GR&R metrics with probabilities of misclassification. Comparison of GR&R Metrics with Probability of Misclassification Using Numeric Simulation A simulation study…

A Comparison of Measurement System Analysis Metrics: Part 1 of 2

The precision of a measurement system is commonly assessed using a gage repeatability and reproducibility (GR&R) study. In Part 1, this article describes available GR&R metrics. Part 2 covers their applicability to two broad cases of comparative study.   Measurement system analysis has been a major part of process characterizations and improvements, with key guidance…

1 comment

Measurement System Redesign and Innovative Data Management

A multinational paper company wanted to reduce its cost of poor quality. The company recognized an opportunity to use Six Sigma concepts to minimize variability in its processes. Senior management was excited about the idea of applying design of experiments (DOE) to uncover the mathematical relationships among the input and output variables. For them, the…

5 comments

The Art of Measuring What Matters

“Ensure that every measure of performance is pertinent to the achievement of a goal or value of your organization. Otherwise, you risk misdirecting the organization.” –Peter Drucker, Management: Tasks, Responsibilities, Practices (Harper & Row, 1974) Even in well-managed, global companies, the failure to measure what matters can lead to unintended consequences. Consider the following real-world…

Characterizing the Measurement Process

Measurement system analysis (MSA) can be fun, always impresses the customer, and can often result in an important surprise or two. Learn why gage R&R is only one part of the equation for achieving near risk free measurements of all types. Characterizing measurement error is one of the most important yet overlooked and misunderstood aspects of…

Measurement System Analysis Resolution, Granularity

Quality improvement methodologies and the analyses that are performed within your organization are only as good as the data on which they are based. That is why it is essential to make sure that your measurement system – your gages, personnel, methods and procedures – is stable and capable of measuring your data before continuing with…

Making Sense of Attribute Gage R&R Calculations

Measurement error is unavoidable. There will always be some measurement variation that is due to the measurement system itself. Most problematic measurement system issues come from measuring attribute data in terms that rely on human judgment such as good/bad, pass/fail, etc. This is because it is very difficult for all testers to apply the same…

19 comments

Attribute Agreement Analysis for Defect Databases

A defect database that tracks errors in processes (or even products) – a database that is so sophisticated that it actually tracks where the defect occurred in addition to the type of defect – can provide powerful information. It can be quite helpful in scoping and prioritizing potential improvement opportunities. But is the data trustworthy?…

Meeting ITIL SLAs: MSA for Project Completion Time

A common service level agreement (SLA) measurement among Information Technology Infrastructure Library (ITIL) practitioners is project completion time, in one form or another. Many use a percent difference measurement between actual and forecasted, others simply subtract the actual completion time from the forecasted completion time. Whatever the final calculation, using the elapsed time between when…

Measurement Systems Analysis in Process Industries

The gage R&R study is the standard tool in the Six Sigma process improvement methodology to evaluate the adequacy of a measurement system with regard to measurement variability. While it is well established and widely used in the discrete manufacturing industry, it is less useful in process industries where the nature of measurements is different,…

The Power of Gage R&R in the Pharmaceutical Industry

There is usually a strong belief that a validated analytical method, either partly automated or fully manual is simply perfect and cannot generate any defect since it complies with highly demanding regulations. Thus, any apparent variation in a production process is automatically attributed to the manufacturing process or raw material suppliers. The latter being also…

Proper Data Granularity Allows for Stronger Analysis

Can we trust the data? This is the fundamental question behind measurement system analysis (MSA). The question can come up in any data-based project. Shortcomings in a measurement system’s accuracy (bias, linearity, stability or correlation) and precision (resolution, repeatability or reproducibility) can obstruct analysis purposes. One often-overlooked aspect of resolution is data granularity, or the…

Trusting the Data: Gage R&R in Transactional Projects

An essential component of any Six Sigma project is the gage R&R step conducted during the Measure phase. Traditional training will cover the full analysis of variance (ANOVA) of a set of continuous data, an attribute gage R&R for discrete data and the destructive gage R&R. Since it is sometimes difficult to apply these tools…

1 comment

A Simple Way to Test Data Without Doing a Gage R&R

In Six Sigma work, practitioners normally are expected to conduct a gage R&R study to verify that that the measurement systems being used are providing measurements free from variations due to repeatability and reproducibility problems. This is usually done in the Measure phase of DMAIC (Define, Measure, Analyze, Improve, Control) prior to data analysis so…

2 comments

Measurement Uncertainty as a Real World Issue

As the industrial world continues to become more competitive, measurement tolerances will become tighter. At the same time, customers insist that products be produced at a lower cost. In this environment, the production floor of Six Sigma companies must continually improve the certainty of measurements without increasing costs. Most companies are at the early stages…

Perception Versus Reality: Importance of Measurement

At a high level, there is usually agreement on the big issues in any healthcare organization. Through observation and feedback alone, key stakeholders may realize there are problems with excessive wait time in the emergency department, or that the first surgical case of the day rarely starts on time, or that it is taking too…

Challenges of Discrete and Attribute Data Measurement

More than ever, companies today realize the importance of measurement – everything from measuring performance to measuring gap closure – in order to achieve goals. Measurement is the process of estimating the ratio of the magnitude of a quantity to a unit of the same type. A measurement is the result of such a process, normally expressed…

Turning Judgment Calls into Reliable Data with Gage R&R

One of the biggest challenges in making improvements in transactional processes is getting data which can be relied upon. There is an abundance of categorical data in transactional areas – situations where a judgment call is required: Is something right or wrong? Is the application complete? What type of error was made on the request…

2 comments