Page 134 - Design for Six Sigma for Service (Six SIGMA Operational Methods)

Quality Function Deployment 109

1. The customer desirability index is obtained from the voice of the
customer activities such as surveys and clinics and is usually rated on
a scale from 1 (not important) to 5 (extremely important) as follows:

Direction of improvement
Extremely important 5.0
Very important 4.0
Somewhat important 3.0
A little important 2.0
Not important 1.0

2. The technical Importance Rating is calculated as follows:
a. By convention, each symbol in the relationship matrix receives a
value representing the strength in the (What, How) cell.
b. These values are then multiplied by the customer desirability index,
resulting in a numerical value for the symbol in the matrix.
c. The technical importance rating for each How can then be found by
adding together the values of all the relationship symbols in each
column.
Technical importance ratings have no physical interpretation; their
values lie in their ranking relative to one another. They are utilized to
determine which Hows take priority and should be allocated the most
resources. In doing so, the DFSS team should use the technical
importance rating as a main metric coupled with other factors like
difficulty, innovation, cost, reliability, timing, and all other measures
in their project charter.

Planning Matrix
The planning matrix is used to make comparisons of competitive performance
and identification of a benchmark in the context of ability to meet specific
customer needs. It is also used as a tool to set goals for improvement using a
ratio of performance (goal rating/current rating). Hauser and Clausing (1988)
view this matrix as a perceptual map in trying to answer the following
question: How can we change the existing product or develop a new one to
reflect customer intent given that the customer is more biased toward certain
features? The product of customer value, the targeted improvement ratio for
the raw (feature), and the sales point, which is a measure of how the raw
feature affects sales, will provide a weighted measure of the relative
importance of this customer feature to be considered by the team.

Hows Correlation (The Roof)
Each cell in the roof is a measure of the possible correlation of two different
Hows. The use of this information improves the team’s ability to develop a
systems perspective for the various Hows under consideration.