Auditing Statistically - A statistical approach to sample sizes

M

M Greenaway

#1
This topic could have gone under the statistics heading - but anyway.

Various discussions have talked about statistics and variance of processes, and i'm sure we all have an appreciation of what it is all about.

Therefore when we conduct an audit, which is a method of 'measurement' like any other (maybe) should we adopt a statisitical approach to sample sizes, plotting and interpretation of data (findings). i.e. just because we find an NC in an audit couldnt it just be that this is a common cause of variance in the process ?

Or am I way off beam ?
 
Elsmar Forum Sponsor
#2
Common Cause NC?

Quote:
-----------------------------------------------------------
Originally posted by Greenway
"just because we find an NC in an audit couldnt it just be that this is a common cause of variance in the process ? "
------------------------------------------------------------

Yes, it could. In fact I suspect a lot NCs are. That could explain repeating nonconformances. The problem may come in the CA. I do not know an auditor (internal/external) that would allow a CA to come to the conclusion that the NC was common cause variation and that no action would be taken. We tend to assume that NCs are special cause variation and can be corrected. This is another case of some good mental chewing material. Thanks I know I’m not going to get much work done today! :eek:
 
J
#3
If we're going to conduct QMS measurment statistically,
how would we conduct a MSA on auditing?:bonk: Don't we have to proof the measurment system first?

James
 
L

Laura M

#4
Interesting question.

I would think that the requirements of internal auditing based on the relative importance of an activity and results of previous audits is the basis for anything statistical. P-chart of N/C's by clause, department, can drive decisions. Of course there is measurement system variation, isn't that what has been extensively discussed in other threads regarding certification audits?

But of course - wouldn't common cause = minor and special cause = major? Well at least a special cause in the negative direction - multiple NC's for a given requirement or in a given department.
They may have not had statistics in mind when they were named minor/major - but it correlates in my mind.

Laura
 
M

M Greenaway

#5
Excellant twist

James

Excellant twist to the original post - yes I think we certainly should proof the measurement system first. Applying MSA methodology sounds good - dont know how it could be applied in practice.

Laura - it sounds like a good correlation between common causes, special causes and minor, major findings. A statistical approach would enable the auditor to classify his findings as minor/major with much greater accuracy, as at present it can be quite subjective.

I think we could be on to something here !
 

Atul Khandekar

Quite Involved in Discussions
#6
Twist !

Applying MSA methodology sounds good - dont know how it could be applied in practice.
Maybe have 3 auditors conduct the audit twice each? ;)

Is there any sort of consensus as to what constitues a minor NC and what makes a major NC? How do you remove the operator (auditor) bias?
 
M

M Greenaway

#7
Its not beyonf possibility that you could set up a controlled situation that your various auditors have to audit, and then compare results.

Removing bias could be done through additional training to the group so that a common understanding exists between them all.

The more I think about it the better it sounds !
 
A

Al Dyer

#8
Iv'e seen audit results succesfully reported using a pareto chart for guidence as long as all NC's have a C.A.

When thought about, all internal audits are controlled statistically because the results need to be reported to management which in turn uses the results to increase or decrease audit frequencies which is basic sampling..

Hope I made sense, the codeine hasn't kicked in yet!:bigwave:
 
M

M Greenaway

#9
Al

Do you think that the current method of auditing, reporting results and determining corrective actions really has any basis on statistcal theory and causes of variation ?

Reviewing audit results to determine whether to increase or decrease audit frequency is only effective if the audit results themselves are based on statistical analysis of the causes of variation.
 
A

Al Dyer

#10
Originally posted by M Greenaway
Al

Do you think that the current method of auditing, reporting results and determining corrective actions really has any basis on statistcal theory and causes of variation ?

Reviewing audit results to determine whether to increase or decrease audit frequency is only effective if the audit results themselves are based on statistical analysis of the causes of variation.
-----------------------------------------------------------------

1a: Statistical theory: Yes, but only rudimentary not to the point of D.O.E.
1b: Causes of variation: See below.

2: I don't see how the cause of a nonconformance in an internal audit has any affect on the +/- frequency of an audit. The causes would come up during the actual corrective action. If there are nonconformances there is increased frequency, more-so with ongoing nonconformances. And if there are ongoing nonconformances it "probably" (depending on the structure if the audit program) is not caused by the audit system but a faulty C/A system.

I believe it comes down to cost effectiveness as to how intricate the internal audit system is linked to statistical methodology.
 
Thread starter Similar threads Forum Replies Date
C List of MDSAP Auditing Organizations Medical Device and FDA Regulations and Standards News 1
A What are the pros and cons of using an audit software for internal auditing? General Auditing Discussions 4
cscalise Suggestions for MDR Auditing tools EU Medical Device Regulations 1
J Auditing of Support Function IATF 16949 - Automotive Quality Systems Standard 9
D ISO 13485, FDA 21 CFR 820 and Auditing the Accounting Department ISO 13485:2016 - Medical Device Quality Management Systems 5
S Risk based internal auditing Internal Auditing 6
Randy Remote auditing (for disaster, disease, disturbance etc...) during the Neo Coronavirus Pandemic and Social Distancing Registrars and Notified Bodies 7
K ANVISA B-GMP Auditing requirements for Contract Manufacturers Other Medical Device Regulations World-Wide 0
F AS9100D Internal auditing requirements Internal Auditing 3
R Does any here use an internal auditing tool that works on different platforms? Internal Auditing 3
W Does anyone have an API Q2 checklist for internal auditing? Oil and Gas Industry Standards and Regulations 1
G Best Practices for IT auditing - Is a session-id necessary for a complete audit trail? IEC 27001 - Information Security Management Systems (ISMS) 0
I Questions to ask when auditing for Organizational Leadership and Planning for the QMS? ISO 9000, ISO 9001, and ISO 9004 Quality Management Systems Standards 3
C CE marking for general IVD (self-certified) & ISO 13485 QMS requirements - auditing EU Medical Device Regulations 6
blackholequasar Internal Auditing Inspiration - Getting volunteers to perform internal audits. Internal Auditing 22
W Internal Auditing carried out by a 3rd party - Review of previous audits AS9100, IAQG, NADCAP and Aerospace related Standards and Requirements 3
tony s What is the automotive process approach for auditing? IATF 16949 - Automotive Quality Systems Standard 2
S Internal Auditing for API Spec Q1 - auditor qualification requirements Oil and Gas Industry Standards and Regulations 6
R I've been auditing for a CB for 18 years General Auditing Discussions 10
P Consultant Auditing Qualifications Requirements ISO 9000, ISO 9001, and ISO 9004 Quality Management Systems Standards 23
E Informational Internal Audits - Wear multiple hats what can and can't I audit (so I'm not auditing my own work) Internal Auditing 144
M We still have not received our certificate due to a 'backlog' with our auditing body Registrars and Notified Bodies 25
N Online Internal Auditing Course for ISO 13485 - Suggestions ISO 13485:2016 - Medical Device Quality Management Systems 8
A Agenda for 8D audit on Supplier's side - Auditing Corrective Actions General Auditing Discussions 5
U Internal auditing - Company employees or contract second party Internal Auditing 10
J Recomended Values - Auditing process in a supplier IATF 16949 - Automotive Quality Systems Standard 18
M Canada - Registrars that allow e-auditing for ISO 9001? Registrars and Notified Bodies 4
K Internal Auditing - Umbrella QMS and Multiple Standards Oil and Gas Industry Standards and Regulations 4
D Auditing Our Outsourced 2nd-3rd Party Internal Audit Company ISO 13485:2016 - Medical Device Quality Management Systems 6
supadrai Auditing Organization dragging their heels on issuing our MDSAP Surveillance Audit Confirmation Letter - everyone is nervous ... are we the only ones? Canada Medical Device Regulations 7
Ed Panek Supplier Auditing - No purchases from our key suppliers in the last 24 months ISO 13485:2016 - Medical Device Quality Management Systems 5
P Auditing "process validation" process 21 CFR Part 820 - US FDA Quality System Regulations (QSR) 2
qualprod Effective Auditing advice needed ISO 9000, ISO 9001, and ISO 9004 Quality Management Systems Standards 16
M Acceptance of remote auditing techniques - Can you help me with my research? General Auditing Discussions 0
GStough Auditing Against Criteria Unfamiliar to Auditee - Yea or Nay? General Auditing Discussions 11
qualprod Auditing Product and Services doubts ISO 9000, ISO 9001, and ISO 9004 Quality Management Systems Standards 3
R Auditing support and management processes General Auditing Discussions 7
F It is acceptable moving remote locations staff to manufacturing plant for auditing? IATF 16949 - Automotive Quality Systems Standard 3
D MSDS / GHS Walk-through / Auditing Occupational Health & Safety Management Standards 6
Pmarszal Supplier Auditing Services (Audit Needed?) General Auditing Discussions 4
S ISO 9001 Audit Observations - Transitioning my career into auditing Career and Occupation Discussions 16
G AS9101 Rev F - Worksheets for internal auditing AS9100, IAQG, NADCAP and Aerospace related Standards and Requirements 11
N API Q2 clause 6.2.2.1 Auditing Outsourced Suppliers Oil and Gas Industry Standards and Regulations 5
M Auditing processes followed by employees placed on client's site Internal Auditing 4
S ISO 13485:2016 and MDSAP internal auditing ISO 13485:2016 - Medical Device Quality Management Systems 6
M Auditing a Contractor in EMS and Non Conformity Report General Auditing Discussions 1
Richard Regalado ISMS Auditing Guideline V2 (based from ISO/IEC 27001:2013) IEC 27001 - Information Security Management Systems (ISMS) 7
S ISO 9001:2015 - Internal Auditing - Audit to the Standard? ISO 9000, ISO 9001, and ISO 9004 Quality Management Systems Standards 6
B Auditing Senior Management to determine the Effectiveness of Management Processes IATF 16949 - Automotive Quality Systems Standard 6
R Internal Auditor auditing Internal Audit Procedure (AS9100) Internal Auditing 18

Similar threads

Top Bottom