Editor | On 12, Jun 1998

Ellen Domb, Ph.D.
The TRIZ Institute, 190 N. Mountain Ave., Upland, CA 91786 USA
(909)949-0857 FAX (909)949-2968 ellendomb@compuserve.com

A recent series of letters from reader Alex Olimpo, educated in the Philippines and working in Singapore, has re-ignited interest in the subject of the use of TRIZ with QFD (quality function deployment.) Since the many of our readers have expressed interest in this discussion, we have moved it out of the letters to the editor column and into the articles section. What follows is a summary of the letters dialog, and an article that was written for the Third International QFD Symposium, to introduce QFD practioners to TRIZ.

In his first letter, Mr. Olimpo said that he thought that QFD, and in particular the Kano diagram, were more generally useful for product development than TRIZ. My reply follows:

Figure 1. The Kano Diagram. The vertical axis measures customer satisfaction, and the horizontal axis measures the technical level of the product or service. Dr. Kano first identified the zones of this diagram. In the basic quality zone, any technical failure causes customer dissatisfaction, and no level of technical excellence causes customer satisfaction—in other words, you can cause the customer to be unhappy, but you cannot cause him to be happy. In the perfomance zone, the more you give the customer, the more satisfied he (or she) becomes. In the excitement zone, the customer is very happy—even if the execution of the concept is imperfect, the concept causes excitement. The pink arrow representing time shows the natural progression of the marketplace. The exciting idea of today becomes the required product tomorrow. A personal example: when it became possible to receive e-mail by voice, so I could take short trips without carryiing my computer, I was excited. I used the service (at extra cost) frequently, and told all my colleagues. A few months later, I started to complain about the slowness of the artificial voice, and the lack of ability to respond with any but a few phrases. The synergy of TRIZ with the Kano diagram should be obvious—TRIZ can keep creating new product and service concepts at the excitement level, while Dr. Kano’s techniques help quantify the customer’s opinions. For extensive information on qfd, see http://www.qfdi.org

I have attached a paper that I presented at the 3d International QFD Symposium on QFD and TRIZ, that is an introduction to TRIZ for the QFD audience, and a brief discussion of how they work together. As a brief overview, TRIZ helps in the planning phase, when you have the customers’ needs and the organizational capabilities, and you find conflicts (the customer needs something you can’t provide, or your method of providing for that need has inherent conflicts)–use TRIZ to create new concepts for product/service delivery. Once you have developed the requirements, use TRIZ to develop multiple product concepts. The Pugh concept selection matrix, used in almost all QFD, is a more powerful tool than the TRIZ tool called “feature transfer”–so you are using TRIZ by another name! And, in production/delivery planning, TRIZ is the natural tool for “bottleneck engineering”–your QFD analysis will tell you where you have problems, and TRIZ will be a primary tool for solving those problems. You can see why this is popular with the QFD folks!

Here is Mr. Olimpo’s response:

Before I go further asking more information about TRIZ, I would like to introduce myself. I am Alex Olimpo responsible for Reliability Engineering for COMPAQ Computers in Singapore. What I normally do is to use the house of Quality (the roof and the relationship matrix) in helping me identify relationship between the WHAT and HOW and conflict between HOW and HOW (interactions).

Sometimes, in generating ideas or new concepts, I recommend mindmapping. How can TRIZ enhance the use of QFD and Mindmapping. I appreciate very much the information you shared to me and this will greatly help me understand on how to use TRIZ with QFD and other tools.

My reply:

TRIZ is based on the patterns found in past inventions, not on the inventions themselves. The pattern that you mentioned with regard to the Kano diagram is an example. I don’t need to know any of the specifics of the invention to know that today’s exciting quality will be come tomorrow’s expected quality.

You have found that QFD now affects everything you do. Now that I have been working with TRIZ for several years, I find that QFD and TRIZ are completely interrelated, at the planning stage, at the concepts stage, and in the development stage. You don’t need to choose one or the other–use them together for best advantage.

Re: Brainstorming (including the affinity chart, mindmapping, etc. ) These are great ways to get to new concepts for what the customer might want. The discipline of QFD gets you to what the customer’s needs really are (not just the team’s fantasy) and the discipline of TRIZ gets you to ways to actually make these a reality that can be developed, produced, and delivered.