Acceptable Outgoing Quality Level (AOQL) aka Acceptable Outgoing Quality (AOQ)

Thread Attachment browser
R

Randy Feliciano

#1
#1
I have seen formulas for AOQ and is at a lost on which one to use.
The inclusion of Probability equation(the one using factorials) is quite laborious.
Others that are quite direct seem contradicting.

Can any one help me compute for the AOQ in a valid direct way using only any or all of the folllowing parameters/entities:
1.) Sample size and lot size;
2.) No of lots inspected and rejected;
3.) no of reject units.

Thanks guys
 
12 questions to ask before buying a QMS
Elsmar Forum Sponsor
E

e006823

#2
#2
Randy Feliciano said:
I have seen formulas for AOQ and is at a lost on which one to use.

Can any one help me compute for the AOQ in a valid direct way using only any or all of the folllowing parameters/entities:
1.) Sample size and lot size;
2.) No of lots inspected and rejected;
3.) no of reject units.
Click to expand...
There is some shareware available at http://www.variation.com/index.html
that will allow you to "take an existing sampling plan and use the software to evaluate it including calculating and displaying OC curves, AQL, LTPD, AOQL, ASN curves and much more. You also specify the desired protection and the program will generate a list of sampling plans that might be used."


Bob
 
Last edited by a moderator:
R

Randy Feliciano

#4
#4
AOQ or AQL

Thanks for the response.

I hope someone out there will take time just like you did.
Thank you.
 
Tim Folkerts

Tim Folkerts

Super Moderator
#6
#6
Randy Feliciano said:
I have seen formulas for AOQ and is at a lost on which one to use.
The inclusion of Probability equation(the one using factorials) is quite laborious.
Others that are quite direct seem contradicting.

Can any one help me compute for the AOQ in a valid direct way using only any or all of the folllowing parameters/entities:
1.) Sample size and lot size;
2.) No of lots inspected and rejected;
3.) no of reject units.

Thanks guys
Click to expand...
The more I think about this, the less value I see in AOQ and the more I see in AOQL (Average Outgoing Quality Limit).


The calculation of AOQ assumes that the defect rate is known and is constant. That requires a process that is in control. However, I concur with Pyzdek's "Quality Engineer Handbook" when he says "... acceptance sampling should never used for processes in statistical control." Basically all you are doing is fishing around for defects to imrpove the overall quality. You ought to just improve the process to begin with.

If it's not in control (or you just don't know if it is in control), then you might expect large variations between lots. If you don't know the true fraction defective, then you can't calculate the AOQ. YOu can sample to look for the bad lots, but you don't know enought to calculate any meaningful overall AOQ.

It's a Catch-22.
If you know the quality, then you shouldn't sample and/or find AOQ.
If you don't know the quality, then you can't calculate AOQ.

However, you can always calculate AOQL. You can try all the different defect rates that might occur and see which is the worst. Then at least you can say "I don't know how good my process is, but I can assure you that after sampling, then the defect rate will average no more than x%."

Tim


P.S. From Pyzdek, the equation for AOQL is
AOQL = y [ 1/(sample size) - 1/(lot size) ]

where y is related to the acceptance number, c.

c y
0 0.368
1 0.841
2 1.372
3 1.946
4 2.544
5 3.174
10 6.535
 
P

Puzzle

#7
#7
Tim,

That is rather excellent.

Not having had to calculate an AOQL before, what figure would be considered good/excellent.

I have to assume the lowest possible.

Am I correct?

Chris
 
You must log in or register to reply here.
Thread starter Similar threads Forum Replies Date
W Misinterpretation of requirement acceptable as root cause? Problem Solving, Root Cause Fault and Failure Analysis 19
J Standard used to determine if check fixture gauge is acceptable Reliability Analysis - Predictions, Testing and Standards 2
M Measurement Error - How to determine what is acceptable? Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 3
M Are Fungal counts acceptable in class 1000 clean rooms? Other ISO and International Standards and European Regulations 2
T ISO 14971-2019 doubt - Evaluate if estimated risks are acceptable ISO 14971 - Medical Device Risk Management 9
samer Acceptable limits for Spills - Tracking Hydraulic Spills ISO 14001:2015 Specific Discussions 3
V Acceptable maximum RSD (relative standard deviation) for an sample size Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 1
B Gage R&R Acceptable (10-30%), deduct Total Variation from Tolerance Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 12
Q Acceptable calibration accuracy of a 60" linear measuring device General Measurement Device and Calibration Topics 16
F It is acceptable moving remote locations staff to manufacturing plant for auditing? IATF 16949 - Automotive Quality Systems Standard 3
Q Is it acceptable to mix components from two different lots into an assembly? ISO 13485:2016 - Medical Device Quality Management Systems 1
C Acceptable NDC for %GR&R part inspection to Tolerance (%Tolerance) Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 3
D Risk Register - have we considered enough and is the format acceptable? ISO 9000, ISO 9001, and ISO 9004 Quality Management Systems Standards 8
K Operator Checks - How to show that they were completed on a checklist as acceptable IATF 16949 - Automotive Quality Systems Standard 2
C Example Work Instruction/Procedure for AQL (Acceptable Quality Level) AQL - Acceptable Quality Level 4
S Dates on Labels acceptable to the USA - GS1 General Specification 3.4.4 Other US Medical Device Regulations 3
E Root Cause Analysis - Is Insufficient Understanding an acceptable Root Cause? General Auditing Discussions 9
W Unattached (stand-alone) Forms acceptable for AS9100C? AS9100, IAQG, NADCAP and Aerospace related Standards and Requirements 7
V Why Gauge R&R 10% is acceptable for variable instruments ? Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 5
X Acceptable methods to store and archive records ISO 9000, ISO 9001, and ISO 9004 Quality Management Systems Standards 7
M Is it acceptable to audit to the Nuclear Principles? Quality Manager and Management Related Issues 9
I Is it acceptable it is to list new products under an existing 510(k)? Other US Medical Device Regulations 14
S If this EN ISO 11137 certificate acceptable for Contract Sterilization? ISO 13485:2016 - Medical Device Quality Management Systems 2
D What is satisfactory & acceptable for Coliform - Staphylococcus - Hands and Surfaces Food Safety - ISO 22000, HACCP (21 CFR 120) 3
S Is a Dynamic Controlled Form acceptable per 21CFR820 Document Control Systems, Procedures, Forms and Templates 3
C Lowest Acceptable Grade for Master Gage Set Calibration and Metrology Software and Hardware 1
B Digital Signature Solutions acceptable to use in an FDA Medical Device Environment 21 CFR Part 820 - US FDA Quality System Regulations (QSR) 4
J Is a ndc less than five is also acceptable? Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 6
T Technical regulations that determine the acceptable limits of cigarettes General Measurement Device and Calibration Topics 4
L IEC 60601-1 3rd edition Clause 9.2.2 Trapping Zone (Acceptable Gaps) IEC 60601 - Medical Electrical Equipment Safety Standards Series 5
N Is it acceptable to sterilize products without claiming and labeling "sterile" ? ISO 13485:2016 - Medical Device Quality Management Systems 6
M Quality Objectives - Acceptable Levels and Functions ISO 9000, ISO 9001, and ISO 9004 Quality Management Systems Standards 37
C What is an acceptable bioburden level or count when working in cleanroom ISO class7 ISO 13485:2016 - Medical Device Quality Management Systems 1
D Is embedding documents within a Contract an acceptable practice ? Contract Review Process 9
B Non Acceptable % Tolerance Result - Decrease Sorting Limits Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 3
F ANSI ASQ Z1.4 - Is the following process acceptable? Inspection, Prints (Drawings), Testing, Sampling and Related Topics 4
C Maximum acceptable Tolerance - Uncertainty Ratio (TUR) General Measurement Device and Calibration Topics 2
S Is it acceptable to have an ASL for Critical suppliers alone? Supplier Quality Assurance and other Supplier Issues 4
S Is this Quality Policy acceptable in the context of ISO 13485? ISO 13485:2016 - Medical Device Quality Management Systems 24
A Help with acceptable screw gage values per standard BS 919 for Go/ No Go gage General Measurement Device and Calibration Topics 4
S What are typical Acceptable Quality Levels (AQL) adopted in Food industry? Food Safety - ISO 22000, HACCP (21 CFR 120) 1
somashekar Who can provide a WHO GMP certificate in India acceptable to the CDSCO Other Medical Device Regulations World-Wide 6
D Root Cause and Corrective Action - Is our Practice Acceptable? ISO 13485:2016 - Medical Device Quality Management Systems 5
W Application of AQL (Acceptable Quality Level) Concept AQL - Acceptable Quality Level 15
H Acceptable Time to provide proof of CAR (Corrective Action Report) Nonconformance and Corrective Action 4
A Sample Size for Mathematical Model with acceptable Confidence Level Using Minitab Software 7
M AQL (Acceptable Quality Level) for Mixed Part Defect IATF 16949 - Automotive Quality Systems Standard 1
C Comparing Two Test Methods - Acceptable Difference(s)? Statistical Analysis Tools, Techniques and SPC 3
S AQL (Acceptable Quality Level) Report Form example wanted AQL - Acceptable Quality Level 1
M What is an acceptable PPM for large volume fasteners? APQP and PPAP 6

Similar threads

Top Bottom