Cascading QFD

[karrde97]

I downloaded your templates and tried them with what we already have. One thing I noticed was that for our organization, we combine the CCR & Targets from Phase 1 into VOC for Phase 2. Your template doesn't work that way. Is that a big deal or not? I'm still trying to get my head around the QFD process and it gets more confusing when you see it run different ways.

[James]

It's quite easy to get confused because different groups do "QFD" differently.  They have different labels.  They have differing numbers of Houses of Quality.  Six Sigma and DFSS groups tend to talk about the House of Quality as being the same thing as QFD.  "True" Quality Function Deployment practitioners (it's actually a full methodology like Lean or DFSS), don't even use the HOQ tool for certain QFD projects.  (See the article "Where Did QFD Get Its Terrible Name?" for more information on that topic.)

To be honest, I am not sure that I understand your question.  Are you concerned about the labels for your requirements, the orientation of your House of Quality, or the succession of your Houses of Quality?

If you are concerned about the orientation, you should read the article "Heading in the Right Direction".

If you are concerned about the labels for the requirements axis, the answer is that the different quality groups/organizations use different labels for the same things.  For example, you used the term "CCR" for "Critical Customer Requirements".  You will often see these labeled as "CTCs" for "Critical To Customer" requirements.  The originators of QFD labeled them as the "Quality Characteristics Hierarchy".  You will also see them labeled as "Functional Requirements" or simply "Hows".  As for the requirements on the other axis, you will see them labeled "Customer Requirements", "Voice of the Customer (VOC)", "Demanded Quality Hierarchy", or "Whats".

I am not sure if I answered your question or not.  If I didn't, will you please explain your concern a little more?  Also, please indicate what "methodology" (Six Sigma, DFSS, Triz, QFD, etc.) you were studying when you learned about the House of Quality matrices?  Knowing this will make it easier to give you a full answer to your question.

[karrde97]

We are actually 'supposed' to be using DFSS QFD. As with most things, our process isn't robust so everyone veers off target when they go to work on their stuff.

[James]

Knowing that it is QFD for DFSS helps.

So was your concern that the orientation of the templates appears to be rotated from what you are used to, that the labels were different from what you were used to, or was it related to something else entirely?

[Glenn Mazur]

"QFD is not a House of Quality!" This was reinforced to us by Dr. Yoji Akao during his first QFD Master Class in 1994. Why the confusion - early adopters of QFD in the auto industry were looking for a shortcut to speed adoption by their supplier base, and so singled out this one tool as the most important one. Eventually, the shortcut got shortcutted again, resulting in many people seeing the tool as no different than the full methodology. It is also worth noting that there is only one House of Quality - it is the pairing of "quality" demanded by the customer and "quality characteristics" in a 2-dimensional matrix. This is the only matix with "quality" in both axes, thus the name House of Quality. All other matrices are houses of function, reliability, parts, etc. and it would be less confusing if things were labeled in this more meaningful way. Ditto for the axis names. "What" and "How" were coined by an engineer at GM (who has since apoligized) and this has led to countless questions about which data goes where in a QFD chart. It is better to label the axes by the data type - cusotmer needs, functional requirements, failure modes, systems, components, manufacturing setup, process steps, etc. Then, you will know what goes where. The what-how problem is exacerbated because in the House of Quality, the "what" rows are actually describing "why" the customer demands something (customer needs), and the "how" columns actually describe "what" the product should do, not how it should do it. (The columns should be technology independent.) Regarding the name QFD, we must thank Mr. Masaaki Imai, author of the book Kaizen, who as one of the first industrial translators, made this recommendation. Dr. Akao told me he favored Quality Function Evolution, but Mr. Imai thought that to be less impressive sounding. Dr. Akao explained the meaning to me as follows: organizations are composed of many functions, such as marketing, sales, engineering, R&D, manufacturing, quality, service, etc. Normally the quality function is the responsibility of the quality department, where the focus is on improving parts and processes that are currently in production. However, for new products, true quality must begin prior to design, which requires the collaboration of marketing, sales, engineering, etc. In other words, the quality function must be deployed to the other functions in new product development. Many books describe the "F" in QFD as referring product function, but this is not correct. It refers to organization function. In fact, half the QFD process is focused on improving the organization and half on improving the product.