Attribute Gage Study

[Vishwadeep Khatri]

Q 535. What is Attribute Gage Study? How is it different from Attribute Agreement Analysis? Provide an example to highlight when will you use one over the other.

 

Note for website visitors - Two questions are asked every week on this platform. One on Tuesday and the other on Friday. 

• All questions so far can be seen here - https://www.benchmarksixsigma.com/forum/lean-six-sigma-business-excellence-questions/
• Please visit the forum home page at https://www.benchmarksixsigma.com/forum/ to respond to the latest question open till the next Tuesday/ Friday evening 5 PM as per Indian Standard Time. Questions launched on Tuesdays are open till Friday and questions launched on Friday are open till Tuesday.
• When you respond to this question, your answer will not be visible till it is reviewed. Only non-plagiarised (plagiarism below 5-10%) responses will be approved. If you have doubts about plagiarism, please check your answer with a plagiarism checker tool like https://smallseotools.com/plagiarism-checker/ before submitting. 
• The best answer is always shown at the top among responses and the author finds honorable mention in our Business Excellence dictionary at https://www.benchmarksixsigma.com/forum/business-excellence-dictionary-glossary/ along with the related term

[Balaji Loganathan]

An Attribute Gage study is a study that studies the bias and repeatability of an attribute measurement system. It is useful to decide which sources are responsible for the variation of the measurement data. The best one of these is a go/no go gage. This gage basically tells you if the part passes or it fails. There are only two likely outcomes. Other attribute measurement systems can have many categories such as very good, good, poor and very poor

 

What is an attribute agreement analysis?

 

Attribute Agreement Analysis (or Attribute MSA) is one of the tools within MSA, used to estimate your measurement system when attribute (qualitative) measurements are involved. With this we can confirm that measurement error is at an acceptable level before conducting data analysis

 

Attribute Agreement Analysis is the type of Measurement System Analysis (MSA) that is used to measure how well an attribute (discrete) measurement system is working. Gage R&R is the type of Measurement System Analysis (MSA) that is used to measure how well a variable (continuous) measurement system is working.

 

The Attribute Agreement Analysis study can be set up in a similar way as a regular Gauge R&R study. A number of parts are selected from the process, and are gage by two or more operators. This doesn’t just relate to Pass/Fail type assessments, such as with Go/No-Go type gauges, but it can also be used to test the reliability of operators where they make assessment on a rating scale.

 

When to Work with Attribute Agreement Analysis ? 

 

Work with Attribute Agreement Analysis if you aim at doing a Gage R&R (MSA) for a test/measurement that does NOT lead to results you could gage with a measurement instrument. we want it if the results are qualitative. Examples:

• Visual quality control of parts.
• Examination of whether the cleaning was done well.
• Check whether a document is accessible.

To Run the Analysis 

 

What is our objective to find out? Accuracy or Precision? Reproducibility or Repeatability? 

 

To Calculate Accuracy 

 

 Understand how well the measurement system comes to the same results as per the “standard”.

 

Calculate % R & R 

 

Shows how exactly the different appraisers agree about results and how precisely one and the same appraiser comes to the same results when measuring multiple times. 

• Total % R&R defines the level of agreement within/ between appraisers and a standard
• Total %R&R should be 100% (when the study conditions are different from reality every result below 100% will lead to a measurement system not worth trusting)
• If the Total %R&R is less than 100% examine the results to see if this is a problem of repeatability, reproducibility or both

[Venugopal R]

Benchmark Six Sigma Expert View by Venugopal R

ATTRIBUTE AGREEMENT ANALYSIS (AAA) is a method of performing MSA (Measurement Systems Analysis). MSA is done to assess reliability of Measurement Systems. When we have an attribute type of measurement;  for example – visual inspection, manual validation of insurance claims, document classification etc., where the decisions are based on human (Appraiser) judgement, and no measuring instrument is involved – the outcome will be categorical (Example – Pass/Fail, Accept/Reject, Good/Bad etc.). For such measurement systems, we can use the Attribute Agreement Analysis to evaluate the acceptability of the system.

 

The AAA helps to evaluate the extent of agreement 'within appraisers', 'between appraisers', 'the accuracy of appraisers' and the 'overall measurement system’s accuracy'.  

 

The Attribute Agreement Analysis is capable of giving 4 outputs, viz.

1.       Within Appraiser variation (Repeatability)

2.       Between Appraiser variation (Reproducibility)

3.       Appraiser vs Standard variation (Appraiser Accuracy)

4.       Overall accuracy (Team Accuracy)

Point nos. 3 and 4 as above will be possible if we use a ‘Master Standard’ for comparing the decisions made by the Appraisers.

 

For example, if Medical Insurance Claims are processed and the acceptability of each claim is judged by few auditors, the AAA would be good method to assess the reliability of the Audit Quality

 

ATTRIBUTE GAGE STUDY is also an MSA methodology, and used to evaluate an attribute measurement system that uses an attribute gauge, which only screens the acceptable and non-acceptable parts, though the parts will have a value for the measured parameter.

 

Attribute Gage Study examines the bias and repeatability of the system. For example, if an air plug gauge is used as a ‘go – no go’ measurement for diameter, the Attribute GageSstudy can be performed to assess the bias and repeatability of the system. For performing the Attribute Gage Study, a few parts are selected such that the range of their dimensions represent the normal operating range. Each part should have a reference value, which is the known and correct value for that part. Each part must be measured repeatedly for multiple times (recommended 20 times) and the number of ‘Accepts’ and ‘Rejects’ need to be recorded.

 

Detailed requirements for the parts are given by AIAG’s MSA reference manual.

 

The Attribute Gage Study report will contain:

1.       Fitted line for ‘% acceptance vs Ref value of measured part.’

2.       Bias (acceptability of bias is based on p-value)

3.       Repeatability

4.       Graph for Probability of acceptance vs Ref value of measured part’.

[Vikas Choudhary]

An investigation into the bias and consistency of an attribute measuring system is known as an attribute gauge study. A 100% end-of-line inspection, for instance, might be carried out by an automatic inspection gauge. This gauge needs to be reliable and reproducible.

It is more common to refer to the study as Attribute Agreement Analysis when the performance of the gauge or technique under consideration is utilized to generate judgements on a non-continuous scale, such as Pass/Fail or a rating

Nowadays, a lot of businesses conduct studies on their measuring devices using gauge R&R. Less well known are the resources that are currently available for conducting comparable studies for non-measurement type instruments, such as Go/No-Go gauges. The study of instruments that measure properties on a continuous scale, such as force, length, viscosity, pH, etc., falls under the purview of gauge research and development. It is more common to refer to the study as Attribute Agreement Analysis when the performance of the gauge or technique under consideration is utilized to generate judgements on a non-continuous scale, such as Pass/Fail or a rating.

 

An Attribute Agreement Analysis study is created like a regular Gage R&R study. A series of parts are selected from the process and evaluated by two or more operators. From this research, it will be possible to determine how consistent operators are in their own ratings and the degree of agreement between operators. If you can set the evaluation criteria for each part, you can also compare the performance of each operator to the criteria.

Attribute agreement analysis studies are not only applicable to pass/fail ratings used in pass/fail gauges, but can also be used to test operator consistency when making ratings on rating scales. increase. Collect survey data and perform analysis using modern statistical software such as Minitab. Graphical output and statistical kappa values can be used to examine operator effectiveness and accuracy in conducting assessments.

[Mayank Gupta]

There were many answers to this question. However, not all were published as some of them were incorrect. The question was a tricky one as it dealt with 2 confusing MSA methods - Attribute Agreement Analysis and Attribute Gage Study. 

Attribute Agreement Analysis is used for discrete data to check for operator agreements on the attributes (there is no gauge being used here). Attribute Gage Study is used when attribute data (like Go/No Go etc.) is being generated using a gauge. 

The chosen best answer is from Balaji Loganathan.

Do review the response from Mr Venugopal R, Benchmark Six Sigma's in-house expert.