How to use CNX? Pareto-Ishikawa-CNX-SOP analysis - PF/CE/CNX/SOP



Hi, after 250 hours of work experience and learning here in my company - internship site, i am not yet finished with my process improvement project. Can anybody there help me?

My professor at the University of the Philippines asked me that the methods that i should follow in the problem analysis part of my manuscript is something like Pareto-Ishikawa-CNX-SOP analysis.

Please, i am quite unfamiliar with the CNX part. Can anybody help me? I tried to research it at but to no avail. Please. Thanks.

Hope somebody helps. :cfingers:
Elsmar Forum Sponsor


Quite Involved in Discussions
Re: How to use CNX?

I was curious myself so I did some searching:

PF/CE/CNX/SOP: A methodology that is used to reduce extraneous variation. It uses process flow diagrams (PF) and cause and effect diagrams (CE) to identify and sort the causes of variation. The causes are further categorized as controllable (can be held constant “C”), noise (too difficult or expensive to control “N”) or experimental (factors which must be investigated to understand their impact “X”). Standard operating procedures (SOP) are used to establish methods for holding the “C” factors constant.

Most of the valid results were about "lean six sigma" and root cause investigations.


Hunkered Down for the Duration
Staff member
Re: How to use CNX?

Thanks, atetsade!

Is anyone else familiar with this technique?


PF/CE/CNX/SOP is part of the 6 Sigma tool set as an analysis tool. The general process is:

PF = Process Flow
–Map or flowchart the process
–Identifies sources of waste, decision points, and loops
–Identifies flow of materials and information

CE = Cause & Effect
–Brainstorm potential sources of variation
–Promotes out of the box thinking and employee involvement

CNX = Constant, Noise, and Experimental
–Classify all sources of variation
–Constant factors can be controlled
–Noise factors cannot be controlled or are chosen not to be held constant
–Experimental factors can be tested at different options or settings

SOP = Standard Operating Procedure
–For all C’s or Constants on the Cause & Effect
–Explain how to hold the factors constant


Thanks for the info, but now that i know the definition of CNX, how do i apply that in my manuscript?

Would be it like a classification type? Like, the C, N and X listed above and putting the right problem under it?

Unlike Pareto, Ishikawa, etc with which I have a good grasp on, i dunno much on how to do CNX... What are the definite criteria for a problem to be defined as C, N X anyway? Thanks so much!!:confused:


Quite Involved in Discussions
CNX is extremely familiar in the context of statistical process control.

The Constant factor of CNX is the same as special causes of variation in SPC. The Noise factor of CNX is the same as common causes of variation in SPC.

You shouldn't have to look too far to find examples of the Experimental factor of CNX.

I highly recommend reading some overview of statistical process control materials. This will elucidate further what you may already know about statistics and reducing variation in the scope of six sigma improvement projects.
Thread starter Similar threads Forum Replies Date
C Scrap Reduction with PF/CE/CNX/SOP Methodology The Reading Room 8
V Pareto Analysis - Six Sigma - 'Productivity Improvement' project Service Industry Specific Topics 1
A How to Subset Pareto Cause in JMP using JSL Software Quality Assurance 4
B Understanding the attached sample Pareto Chart for Customer Complaint Quality Tools, Improvement and Analysis 20
M Minitab Pareto Chart Text Adjustment Using Minitab Software 10
M Definition Pareto Analysis (80/20 rule) - Definition of Definitions, Acronyms, Abbreviations and Interpretations Listed Alphabetically 10
K Pareto Analysis for Common Defects - To pareto or not to pareto Quality Tools, Improvement and Analysis 9
L Pareto question Microsoft Excel Excel .xls Spreadsheet Templates and Tools 6
S Getting the Right Things Done - A useful way to apply Pareto analysis The Reading Room 1
J How to connect FMEA, Control Plan, G8d, 5Whys and Draw the pareto Nonconformance and Corrective Action 0
V Minitab Pareto - Trying to plot a relation of Count and Cycle Time Using Minitab Software 5
A Does anyone actually do a Pareto of the Top 5 (highest) RPN's of PFMEA? FMEA and Control Plans 8
P Pareto Charts - Analytical tools - Form Attached Quality Tools, Improvement and Analysis 5
W Sorting in Microsoft Excel .xls - I want to create a Pareto Chart Excel .xls Spreadsheet Templates and Tools 21
Q The Pareto Principle - Organizational Change Philosophy, Gurus, Innovation and Evolution 10
L Management Review Minutes and Pareto Charts Management Review Meetings and related Processes 10
J Vital few or highest pareto? Which issue should be the priority? Preventive Action and Continuous Improvement 45
N What does a Pareto chart tell me that a pie chart doesn't? Quality Tools, Improvement and Analysis 12
V Free Quality Tools for drawing Ishikawa Diagram, Pareto Diagram, Histogram, etc. Quality Assurance and Compliance Software Tools and Solutions 7
V Seeking: Free Quality Tools - Ishikawa diagram, Pareto diagram, histogram, etc. Quality Tools, Improvement and Analysis 5
D Pareto vote - Could someone explain the pareto vote process? Quality Tools, Improvement and Analysis 6
V Risk Assessment Precedence - FMEA > Risk Matrix (Modified PHA) > Ishikawa? FMEA and Control Plans 11
Y Control Charts + Ishikawa Manufacturing and Related Processes 26
V Quality Gurus Comparison - Deming, Juran, Crosby, Ishikawa and Taguchi Philosophy, Gurus, Innovation and Evolution 1
M Ishikawa Fishbone for Electronics Assembly Quality Tools, Improvement and Analysis 5
Similar threads

Top Bottom