# MSA (Measurement System Analysis) for Characteristics with One Tolerance Limit

A

Hello all,

I have the following problem: a need to make a MSA (Cgk and R&R) study for a characteristic that has just upper tolerance limit. Far as I know of you can not realize the MSA study for characteristics that has just one of tolerance limit. However, I would like to now if someone had this issue before and what I can do in this case?

#### Jen Kirley

##### Quality and Auditing Expert
Re: MSA for charatesristics with one tolerance limit

Welcome to the Cove!

My understanding of MSA is that it's not limited to 2-sided specifications. The studies are about measuring and analyzing error, which can certainly be done with a one-tailed test.

Does anyone disagree?

Raytheon put out a nice little tutorial and we have a number of templates in the Post Attachments List (see the green button in the header) for your use.

Last edited:

#### Jim Wynne

<snip> I have the following problem: a need to make a MSA (Cgk and R&R) study for a characteristic that has just upper tolerance limit. Far as I know of you can not realize the MSA study for characteristics that has just one of tolerance limit. However, I would like to now if someone had this issue before and what I can do in this case? <snip>

Whether the tolerance is bilateral or unilateral, it's the total tolerance spread that's used in GR&R. For example, it the tolerance is ?.005, the total tolerance is .010. If the tolerance is +0/-.010, the total tolerance is also .010.

You might be thinking of Cpk calculation which does assume a bilateral tolerance.

U

#### Uchiha

You might be thinking of Cpk calculation which does assume a bilateral tolerance.

I don't think Cpk calculation assumes any bilateral tolerance. What is more, only Cpk (or Ppk) can be calculated in case of a unilateral tolerance. Cp (Pp) cannot...

Someone correct me if I am wrong.

#### Jim Wynne

I don't think Cpk calculation assumes any bilateral tolerance. What is more, only Cpk (or Ppk) can be calculated in case of a unilateral tolerance. Cp (Pp) cannot...

Someone correct me if I am wrong.

The purpose of Cpk is to provide an indication of how well a process is centered between upper and lower specification limits. Cpk/Ppk, which are dubious metrics to begin with, make no sense in terms of a unilateral tolerance.

U

#### Uchiha

The purpose of Cpk is to provide an indication of how well a process is centered between upper and lower specification limits. Cpk/Ppk, which are dubious metrics to begin with, make no sense in terms of a unilateral tolerance.

Exactly. And that is by calculating two Cpks to determine to which side is your process "shifting"...

So in case of, let's say, only an upper tolerance limit, calculating the upper Cpk will let you know how close is your data to the upper TL. Obviously the lower side Cpk is not defined in this case, neither is the Cp (Pp)...

#### Jim Wynne

Exactly. And that is by calculating two Cpks to determine to which side is your process "shifting"...

So in case of, let's say, only an upper tolerance limit, calculating the upper Cpk will let you know how close is your data to the upper TL. Obviously the lower side Cpk is not defined in this case, neither is the Cp (Pp)...

No. Cpk assumes a bilateral tolerance. If there is no upper and lower tolerance limit, there is no target to use as a reference point. The idea is to determine how far the mean is from the nominal value. How can you calculate upper and lower Cpk if only upper or lower exists?

#### Bev D

##### Heretical Statistician
Super Moderator
Well the Cpk/Ppk formulas don't include the target/nominal. htey only include the upper and lower spec limits. So Jim can you clarify your understanding?

#### Jim Wynne

Well the Cpk/Ppk formulas don't include the target/nominal. htey only include the upper and lower spec limits. So Jim can you clarify your understanding?

Instead of nominal I should have said "mean."

MSA on automated measurement system - Multiple Step Vision System Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 3
Measurement system analysis - Can you help me about implementation MSA for CMM device Manufacturing and Related Processes 2
N Justifications for not performing MSA (Measurement System Analysis) Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 6
IATF 16949 7.1.5.1.1 Measurement System Analysis (MSA - Die casting) IATF 16949 - Automotive Quality Systems Standard 5
B Camera Vision System Measurement System Analysis (MSA) Reliability Analysis - Predictions, Testing and Standards 3
IATF 16949 7.1.5.1.1 Measurement System Analysis (MSA) - Visual Inspection IATF 16949 - Automotive Quality Systems Standard 14
C MSA (Measurement System Analysis) - Instrument Selection Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 4
C MSA (Measurement System Analysis) - Dimension Selection Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 5
S MSA (Measurement System Analysis) - Process Tolerances Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 9
MSA (measurement system analysis) on Flammability tester? Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 2
B Selecting Parts for an MSA (Measurement System Analysis) Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 7
T MSA on Camera Vision System and other Process Measurement Systems Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 3
MSA (Measurement System Analysis) and Dimensional Tolerances Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 1
F MSA - Measurement System Analysis Attribute Data Crosstab sheet APQP and PPAP 1
R Destructive Non Reproducibility MSA (Measurement System Analysis) Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 8
M MSA (Measurement System Analysis) on a Photospectrometer Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 9
T MSA (Measurement System Analysis) Competency Test Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 11
B Surface Finish Equipment MSA (Measurement System Analysis) Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 5
Is MSA useful to prove a Measurement System after Relocation? Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 2
B Very interesting article concerning MSA (Measurement System Analysis) Book, Video, Blog and Web Site Reviews and Recommendations 8
B Wait or not wait? MSA (Measurement System Analysis) Actions Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 2
B MSA (Measurement System Analysis) - Results and Actions Taken Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 12
C Attribute Measurement System Analysis (MSA) Template Document Control Systems, Procedures, Forms and Templates 0
D MSA (Measurement System Analysis) on a Bore Measurement - Good or bad result? Six Sigma 9
Is MSA (Measurement System Analysis) Required for Degradation Testing? IATF 16949 - Automotive Quality Systems Standard 1
MSA (Measurement System Analysis) - Do we have control of all states in the chart? Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 5
E MSA (Measurement System Analysis) Study on an Automated Process Quality Tools, Improvement and Analysis 4
Is a MSA (Measurement System Analysis) needed on these two tests Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 8
C What is the most appropriate MSA (Measurement System Analysis) Study Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 4
M How to Stack for MSA (Measurement System Analysis) in Minitab? Using Minitab Software 1
V Is MSA (Measurement System Analysis) required for Weighing Scale? Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 4
Linearity Problem (MSA - Measurement System Analysis) Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 5
B Gage R&R/MSA for In Process Measurement System in a Turning Machine Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 1
S Weighing Scale MSA (Measurement System Analysis) Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 2
MSA Studies on each Equipment, each Measurement System or Family in Control Plan? IATF 16949 - Automotive Quality Systems Standard 35
I Destructive Testing Measurement System Analysis (MSA) Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 18
S Sample Size for Attribute MSA (Measurement System Analysis) in 4th Edition Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 1
Measurement System Assessment (MSA) - Water Crackle Test General Measurement Device and Calibration Topics 2
S Choosing Parts for Attribute MSA (Measurement System Analysis) in 4th Edition, pg 132 Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 2
A Yearly MSA (Measurement System Analysis) & Capability Study - TS 16949 Requirements Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 2
Z MSA (Measurement System Analysis) for a .0003" tolerance feature Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 1
Attribute MSA (Measurement System Analysis) - .xls Form attached Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 27
S MSA (Measurement System Analysis) for Medical Device Manufacturers Other US Medical Device Regulations 3
Visual Inspection of a Weld - MSA (Measurement System Analysis) Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 4
K MSA (Measurement System Analysis) on Multi-Phase Measurement System Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 12
A Width and location errors in MSA (Measurement System Analysis) Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 10
M Measurement System Analysis (MSA) Procedure template Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 3
Intro to Measurement System Analysis (MSA) of Continuous Data – Part 5b: R&R Imported Legacy Blogs 14
Intro to Measurement System Analysis (MSA) of Continuous Data – Part 5a: R&R Imported Legacy Blogs 11
Intro to Measurement System Analysis (MSA) of Continuous Data – Part 4: Stability Imported Legacy Blogs 2