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OM4 Chapter 6: Goods and Service Design
Discussion Questions
1. How might today’s technology, such as the Internet, be used to understand the voice of the
customer?
Consumers provide a lot of “free” information in the form of blogs, discussion groups, web
site product reviews, and so on. Companies can leverage this information by carefully
monitoring comments about their products as well as their competitors’ products. The cost of
2. What lessons can be learned from the LaRosa’s Pizzeria boxed example?
Customer requirements, as expressed in the customer’s own terms, are called the voice of the
customer. They represent what customers expect a product or service to have or to do. The
3. In building a House of Quality, what departments or functions should be involved in each step
of the process?
Voice of the customer: Marketing
Technical features: Design, Operations, and Marketing
4. Explain how the goal post view of conforming to specifications differs from Taguchi’s loss
function. Would you rather buy an automobile where suppliers used the goal post or Taguchi
models? Why?
Adopters of the Taguchi model try to design processes to hit the target value where any
You most likely have many examples you can share with students but here is a simple one. If
a shaft on an automobile transmission is close to the high end of the goal post range
(specification) and the hole that it goes through is close to the low end of its range then what
happens? The shaft fits too tightly in the hole as it rotates and creates friction and heat and
5. Propose an explicit service guarantee for an airline. Clearly explain why you included the
features of your service guarantee (maximum of one page). Do you think that an airline
would adopt it? Why or why not?
At one extreme, students may write something like “XYZ Airlines will give you a credit on
future flights if we do not provide 100% customer satisfaction. To invoke the service
At the other extreme, students may write something like “XYZ Airlines will listen to your
complaint and make every effort to make you happy and comfortable. Please download our
Most airlines have service guarantees somewhere in between these two extremes subject to
Problems and Activities
(Note: an asterisk denotes problems for which an Excel spreadsheet template on the CourseMate
Web site may be used.)
1. Build a House of Quality (showing only the Voice of the customer, Technical features,
Interrelationships, and Relationship matrix from Exhibit 6.2) for designing and producing
chocolate chip cookies. The voice of the customer consists of:
a. Soft
b. Fresh
c. Bittersweet
The technical features identified are
a. baking temperature
b. baking time
c. type of chocolate
Clearly explain your reasoning for your ratings of the interrelationships and relationship
Below is a HOQ template that students can use (you can copy it and embed it on a
PowerPoint slide for class discussion). There is no one correct solution, but the answers
Students should also include relationships between technical requirements in the roof. For
2.* Suppose that the Taguchi loss function for some part is estimated to be L(x) = 6,800 (x
T)2. Determine the loss if x = 6.09 inches.
The Taguchi Loss Function is:
6.09 is beyond the speci&cation of 6.05 so we expect the Taguchi economic
The Excel template Taguchi can be used to compute the loss per part; use
3.* A quality characteristic has a design specification (in cm.) of 0.200 0.04. If the actual
process value of the quality characteristic is at the boundary of the tolerance on either side,
The Excel template Taguchi can be used to compute this:
4.* For the situation in Problem 3, what are the economic design specifications if the cost of
inspection and adjustment is $7.50?
Using the logic in the Solved Problem in the chapter, the highlighted portion of the table
5.* Suppose that the design specifications for hydraulic cylinder are 10.00 0.10 centimeters,
and that the Taguchi loss function is estimated to be
L(x) = 2,400 (x T)2.
(a) Determine the estimated loss for a production order if the quality characteristic under
study takes on a value of 10.04 and 100 parts are produced.
If 100 parts are produced at this value, the total loss is 100(3.84) = $384.
(b) Assume the production process is recalibrated weekly and a new sample of cylinders
If 100 parts are produced at an average x-bar of 9.789 centimeters the loss per unit is
Thus the total Taguchi economic loss is $10,685. In (a) the economic loss was low and
actual process performance was very close to the target design specification but in (b) the
6. The service center for a brokerage company provides three functions to callers: account
status, order confirmations, and stock quotes. The reliability was measured for each of these
services over one month with these results: 0.85, 0.72, and 0.96, respectively. What is the
overall reliability of the call center?
Because this is a series system, reliability = (0.85)(0.72)(0.96) = 0.58752
7. Two cooling fans are installed in some laptop computers. Suppose the reliability of each
cooling fan is 0.98. What percent improvement in reliability does adding the second fan
provide?
8. Given the following diagram, determine the total system reliability if the individual
component reliabilities are: A = 0.94, B = 0.90, and C = 0.87. (Hint: Use equations 6.2 and
6.3 and note that the reliabilities of the parallel components are different.)
First &nd the reliability of the parallel subsystem BC: Reliability = 1 - (1 -
Make sure students understand these parallel reliability computations must
9. A simple electronic assembly consists of two components in a series configuration with
reliabilities as shown in the figure below.
A
B
C
A
B
(We’ll call Design Option A)
Engineers would like to increase the reliability by adding additional components in one of the
two proposed designs shown below:
(Design Options B and C)
a. Find the reliability of the original design.
b. Explain how the configurations of the proposed designs differ.
Design option B places two components in series (.9 and .95) and
Make sure students understand that for option B, series reliability
c. Which proposed design has the best reliability?
Option B
Option C
First parallel reliability = 1 - (1 - 0.9)(1 - 0.9) = 1 – (.1)(.1) = 1 – 0.01 = .
99
