Quality Function Deployment
* Methodology for defining the customer's
desires in the customer's own words, prioritizing these
desires, translating them into engineering requirements, and
establishing targets for meeting requirements.
Tool for defining the "right" problem to solve.
-Developed in Japan in 1970's - Mitsubishi
-Introduced in US in 1980's (Hauser and
Clausing, Harvard Business Review, May-June 1988).
*Also known as:
-Voice of the Customer
-House of Quality
-Matrix Product Planning
*Uses a series of matrices to structure information
acquisition and documentation.
Figure 1. General organization of a QFD matrix.
1. Identify customers (both internal and external).
2. Create a list of customer requirements (WHATS).
* Record customer responses to the question: "What are the
important (qualities, characteristics, elements, features) of
* Record in customer's own words - "Voice of the Customer."
* Categorize hierarchically (primary, secondary, tertiary,...).
3. Prioritize the customer requirements on a scale of 1-5.
4. Compile list of design requirements (HOWS) necessary to achieve
the market-driven whats.
* Each requirement should be quantified.
* Arrows show direction for improvement (up for increasing, down
for decreasing, etc.)
Figure 2. Start with WHATs and HOWs.
5. Determine relationship of design requirements to customer
* Cell strengths quantify the importance of each HOW to
achieving each WHAT.
No mark for no relationship
Figure 3. Adding correlations between WHATs and
6. Determine how the customer perceives competitors' abilities
to meet requirements.
* Competition benchmarking.
* Rate competitors on a scale of 1-5 with respect to each
7. Rank the technical importance of each design requirement.
* Absolute rank is total of relationship value (quantify step 5
relationships) times customer importance ranking.
* Relative importance is based on assigning ordinal ranking to
each design requirement based on absolute rank (from previous
8. Rate the technical difficulty of each design requirement so
design team can focus on the important/difficult HOWS.
9. Establish correlation matrix (roof of House of Quality) to
determine interrelationships of design requirements.
Strong positive interaction
Strong negative interaction
10. Determine target values for the design requirements (HOW MUCH).
11. Areas that require concentrated effort are identified. Key
elements are identified for follow-up matrix development.
Assessment of technical difficulty and importance are useful in
identifying these elements.
Figure 4. QFD matrix with objective measures added.
Figure 5. Completed QFD matrix.
* The importance of QFD:
- Provides a framework for upfront planning and product
- Uses multi-functional teams to enhance design and decision-making.
- Promotes teamwork (necessary for Concurrent Engineering).
- Maintains customer ideas and requirements, in the customer's
words, throughout the process.
* Engineered products adhering to customer wants result in