Ask A Quality Professional

1.  Use of Contradiction Matrix for Root Cause Analysis

Posted 13 days ago
Does anyone has any experience on Contradiction Matrix tool for RCA?
What are the benefits and drawbacks?

Is this your preferred tool?

Thank you,

Bart Lapa
CAPA Engineering

2.  RE: Use of Contradiction Matrix for Root Cause Analysis

Posted 12 days ago


I am not familiar with the contradiction matrix.

I generally use a 5 whys analysis and in previous jobs used expanded 5 whys and FTA.

The expanded 5 whys was 3 sets of 5 whys; 1 set each for Prevention, Detection and Containment.

I was used for software faults that became customer found defects.


Mike Williams

Process Engineer | Engineered Products

Johns Manville | A Berkshire Hathaway Company

2235 Highway 411 North

Etowah, TN, 37331

Phone: +1-423-263-6213

Mobile: +1-423-435-5182




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3.  RE: Use of Contradiction Matrix for Root Cause Analysis

Posted 12 days ago
Hi Bart

I've never used the Contradiction Matrix for RCA, and while I haven't seen anyone else do so either, I have heard that it can be done.  Generally the Contradiction Matrix is used during innovation rather than problem solving, but some problems are fixed using innovation so there's certainly overlap.

Your particular situation should determine the best tool to use, if your situation involves resolving contradictions then this tool could be useful for you.

Please let us know if you use it and how if works for you.

Best wishes

Claire Everett
Prosegur Australia
St Leonards

4.  RE: Use of Contradiction Matrix for Root Cause Analysis

Posted 11 days ago

Thank you for you reply.

Contradiction Matrix for RCA is not a new concept, and many of us have used the concept of it without knowing it name.

The way that we are using it currently is in the form of a an excel spreadsheet with potential root causes listed on the left side of the sheet from top to bottom while the known facts are listed across the first row.  The idea is to find facts that either support the potential cause or facts that refute (contradict) potential causes.  This tool examines each fact against the potential cause to asses if the cause can be eliminated or whether is should be examined more.

One example may be that:
Potential Root Cause:  Car's gasoline was contaminated with diesel fuel by driver pumping diesel fuel into gasoline engine.
Contradiction fact may be:  Diesel nozzle pump has larger diameter and it will not fit automobile inlet.

There for the potential cause can be eliminated and a different cause needs to be evaluated in order to explain diesel fuel contamination inside the engine.

I am still learning the benefits of this particular tool vs other tools.


Bart Lapa
CAPA Engineer
Cook Medical
Winston Salem NC

5.  RE: Use of Contradiction Matrix for Root Cause Analysis

Posted 11 days ago
Hi Folks,

I have been intrigued by this discussion. I thought I would weigh in
on this. Generally the contradiction matrix is used in the design
process to identify where there is a "contradiction" which when
resolved leads to an innovative feature which could lead to a new
product. It is often found in the TRIX toolbox.

There is no reason why it should not be used where needed. Keep in
mind it does not identify a root cause but it might get you closer to

I hope that helps.



Dr. Joseph A. DeFeo
Chairman & CEO Juran

6.  RE: Use of Contradiction Matrix for Root Cause Analysis

Posted 10 days ago



Could you post a link to a Triz "toolbox" where this could be found?


Thank you,

Audrey Ehrman

Sr. Quality Technician, III



725 E University Dr

McKinney, TX 75069

Phone: 972.547.6020 : Ext 1262

FAX: 972.542.0097


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7.  RE: Use of Contradiction Matrix for Root Cause Analysis

Posted 12 days ago
It sounds like a version of "Is / Is Not", although I'm not familiar with the term Contradiction Matrix.

When using "Is / Is Not" it helps to clarify and define scope.

Here's an example: