Family Vacations and Quality Function
Deployment
A Case Study in the Application of QFD
Philip Mayfield
Many people who have heard of QFD (Quality Function Deployment) would like to understand
more about this powerful tool. This article/case study serves as an introduction to
the basics and provides a simple example application of QFD. Later, you can build on this according to your needs. Below is an
empty first house of quality – or as it is often referred to, “House 1”.
Initially, a House of Quality can be a bit daunting, but it is not as
difficult as it looks.
After reading this article, you will be well on your way to using this
powerful tool.
Many people have difficulty learning from theory alone; for that reason, it is often helpful to clarify a new concept by using an example. Since this article is “general” – that is, it isn’t product design oriented, IT centric, or project management specific – I chose a project that most of you have dealt with in the past: the Summer Vacation. Without doubt, a summer vacation is a project that presents parameters involving specific requirements and desires. Because you have probably encountered this process on more than one occasion, hopefully, you can relate. It might also provide a bonus; perhaps it will assist in avoiding a disastrous vacation.
In the summer of
2007, my wife and I were planning our summertime family vacation.
We decided to take our two children to the Florida Keys for one
week. Of course, going on vacation isn’t as simple as merely throwing
some clothes in a suitcase and heading for the beach. Worst case
scenario: after a 6 hour car ride, you discover you are missing your
child’s favorite stuffed animal, setting the tone that the week will be
unpleasant at best. To avoid this, we use QFD to ensure we will meet our
requirements. To keep this example short, I have left out a few of the
requirements, but you should be able to follow the methodology easily.
Step #1: Gather the Requirements
One of
the objectives of QFD is to make sure that all of the customer’s goals
(in this case my family’s goals) or requirements are met. Of course, to
meet the customer’s requirements you must first gather the requirements.
One of the most commonly reproduced mistakes when implementing QFD is
either to skip this step or not perform it fully. To ensure you are
meeting your customer’s requirements, you must first identify the
customer. Thus, before leaving the requirements-gathering phase you
should be able to answer these two questions.
What do they want from the
product/service/process?
My
intent with this article is to introduce QFD and not delve into
multi-dimensional market segmentation, so I will simply answer the first
question as…
Who
are my customers?
Answer: My customer(s) is
myself, my wife, and my two children.
In the
world of QFD, my family is dubbed the “market segment”, and we are
targeting this market segment with our QFD. Within a segment, you will
have more than one voice. Another common mistake in QFD is to listen to
one customer within a segment and assume he or she speaks for the entire
segment. In planning a family vacation, my wife’s and children’s needs
should be considered. Starting with the first voice (mine) I need to ask
myself the following question:
What
do I want from this vacation? Answer:
I
would like the vacation to be affordable and I would like to avoid
repeated questions along the lines of, “Daddy, are we there yet?” I will
shorten these to the requirements “Affordable” and “Painless Trip”.
However,
when I asked my wife what she wanted from this vacation, she answered,
“I don’t want to be stressed.”
When I
asked my children, they both answered unanimously, “We want to have
fun!”
At
this point, I want to stop for a moment and discuss the importance of
what just occurred. We as humans have a tendency to consider what
we want or perceive to be
important as actually being the “key requirements”. It would be easy for
me to dismiss my kids with “Vacations are always fun” or “Who couldn’t
have fun at the beach” – no future action required. Similarly, I could
dismiss my wife’s concerns with “Once you get to the beach, all your
stresses will melt away.” Whether you are utilizing QFD for vacation
planning, the design of a new MP3 player, or a new loan approval
process, you must fight this natural tendency to consider
your thoughts/desires/ideas
as more important than the customer’s.
At the
end of this phase, my requirements list boils down to: Affordable,
Painless Trip, Worry Free, and Have Fun.
QFD Key #1:
Ensure you know who the customers are for the product, service, or
project. Work to obtain requirements from a representative sample
(multiple customers) within the targeted market segment. Strive to
gather all the requirements and do not dismiss requirements that differ
from your own.
Step #2: Insert Whats and Importance Ratings
We
can’t start filling out the 1st HOQ without first
understanding a little about it. Below is a picture of the typical view
of House #1. On the left hand side go the
Whats and across the top go
the Hows.
In this case, the
Whats are my requirements
(Affordable, Painless Trip, Fun, and Worry Free), which I gathered in
Step #1. The matrix below shows House #1 with the
Whats completed.
We are now ready
for the “Importance Rating”. The Importance Rating allows us to
prioritize the requirements. Typically, a 1 through 5 scale is used with
the most important requirement assigned a value of 5 and the least
important requirement assigned a value of 1. In our case, the
requirement to be “Worry Free” came from my wife, so it clearly gets the
“5” and my requirement to be Affordable is assigned a rating of “1”.
There are more rigorous methods to rank order priorities, such as
pairwise comparison, but we shall leave that for a later article. Our
House #1 now looks like the following.
Step #3: Brainstorm “Hows” and Enter in Top Row
Now that we have
established the Whats, we
need to answer the question
“How?” This is typically a brainstorming activity that is best done
with the customer. In order to complete the
Hows, ask yourself the
following question:
How will I ensure all of the Whats are addressed (will
occur)? In other words, what steps/actions/goods/services do I need to
perform/acquire/purchase to ensure that the
Whats are all met?
Let’s
start with our first “What” – “Affordable”. I need to know,
How can I ensure the vacation is
affordable? This leads to another QFD key.
QFD
Key #2: Avoid the temptation
to make the top of House #1 too detailed.
I could easily start listing things like, “Inexpensive Hotel”, “Turn off Air Conditioner while gone”, “Cook meals in room”, etc. Instead, I will condense all of this into a simple statement: “I would like the vacation to cost less than $1,000”. My “How” is to keep the total cost of the vacation under $1,000 (in later articles we will address how to do this with House #2).
I then
moved onto my second requirement: Painless Trip. The question that needs
to be answered is “How can we make the trip to the Florida Keys
painless?” This leads to more questions like “What makes trips painful?”
and “Whose pain are we referring to?” The result of our discussion was
that car games are fun for children for about two hours; after that they
start in with “Are we there yet?” And, as those of you with children
know, the affect worsens as the children tire.
Therefore, the answer to the question “How will we have a
painless trip” is “Leave prior to 10am with DVD player in car”. The
“leave prior to 10am” part ensures that we arrive in the Keys before the
children get tired, and “with DVD player in car” ensures that the kids
have something to do other than find all the letters of the alphabet on
license plates.
My third
requirement was for the vacation to be “Worry Free”. I need to answer
the question… “How can I make the vacation worry free?” This leads to
another key of QFD.
QFD
Key #3: Customer involvement
is critical in the success of any QFD implementation. Conversations with
your customer become more productive when you attempt to understand
their requirements in greater detail.
For
example, I need to understand the elements of vacation that “worry” my
wife. It turns out that the worry is centered on forgetting something –
the previously mentioned favorite stuffed animal, allergy medicine,
snacks for the car, to turn off the oven, etc. Once I understand this,
the answer to “How can I make the vacation worry free” becomes “Make and
use a pre-departure checklist”.
My fourth requirement, to have “fun”, probably seems like the easiest but
turns out to be the hardest. I need to answer the question “How do we
have fun on vacation?” To be completely honest, I
failed to answer this question
on far too many vacations. My initial reaction was to “do stuff in the
Florida Keys”. One of the reasons for going was to visit a friend who
had recently moved to Key West. I needed to add to this limited list or
the vacation would rapidly become boring.
After a quick internet search, I found a Turtle hospital, as well
as a marine center called “Theater of the Sea”. At this point, my
activity list resulted in the following.
- Visit friend
in
- Turtle
hospital (2 hours)
- Theater of
the Sea (1 day)
We
have 7 days of vacation planned and less than three days of activities
available. My “Have fun” is in jeopardy. This leads to yet another key.
QFD Key #4: QFD can keep you
from pursuing products/projects/processes that are not feasible. It is
entirely possible that the product/project/process cannot meet all of
the Whats. This is seen as a
negative by many, but I would much rather go in with eyes wide open.
When this happens, we can reduce the requirement set (make a smaller
market segment happy), abandon the project, or look for a new and
innovative way to make the Whats
feasible.
Luckily,
another solution presented itself. It turns out that most of the
activities in the Keys revolve around fishing and snorkeling/diving.
Since we recently purchased a boat, the options of activities expanded
to include general boating (exploring the islands), fishing, snorkeling,
tubing, and wakeboarding. Thus, the “How” becomes “Take boat and local
activities”.
The
current state of House #1 is shown below. Note that the
Whats are on the left side
and the Hows are across the
top.
Step #4: Fill Out the Roof of House #1.
The
intent of the roof of House #1 is to note when requirements are
correlated. Requirements are correlated when they tend to go up and down
together. For example, “Cost < $1,000” and “Take boat and local
activities” trend together. That is, as we take our boat and do local
activities, the cost will go up. Since an increase in the use of the
boat is desirable and an increase in cost is not desirable, they are
negatively correlated. For this reason I have placed a “- -“ in the
intersection between the two columns. The “- -“ signifies that these two
Hows are highly negatively
correlated. This leads to yet another key.
QFD
Key #5: Correlations serve
as early warning for Hows
that might not be feasible. It may not be possible to take the boat and
still have the vacation come in under $1,000. Understanding this now
warns us of this possibility so that we can do additional investigation
and prevent an unwelcome surprise later.
Step #5: Complete the Correlations
At
each intersection of the Whats
and Hows we need to put in a
correlation. In this phase we ask ourselves the question, “To what
degree does the How fulfill
the What?” The correlations
are typically defined as …
Strong
Correlation = 9
Moderate Correlation = 3
Weak Correlation = 1
No Correlation = 0 (or blank)
The
first pass of correlations is trivial. Each
How which was included
specifically for a What
typically has a strong correlation. For example, to what degree does
“Cost < $1,000” fulfill the requirement to be affordable? Since we
created “Cost < $1,000” this should be a correlation of 9. After our
first pass, we have the following House #1.
Before
we move on, there might be some additional correlations to consider. We
should look at each of the intersections to determine if there are other
correlations. For example, to what degree does “Make/use pre-departure
checklist” correlate to “Painless trip”? In other words, will the
checklist serve as more than just a way to facilitate “Worry Free”? In
this case, we decided that it would. The creation of the checklist will
ensure that we don’t forget key items that would be required on the trip
(DVDs and snacks, for example). For this reason, we assigned this a
value of 3. At this point, we have the following House #1.
At the
bottom, we need to calculate a Raw Score. The Raw score is the sum of
the product between the importance rank and the correlation.
SnapSheets XL
calculates this value automatically and will also calculate the Relative
%. The Relative % is the percentage of the total score that each
How contributes. In this
example, the total Raw Score is 9 + 18 + 36 + 51 = 114. The Relative %
for “Cost < $1,000” is 9/114 or 8%.
Step #6: Inspect
Results and Edit as Required
- Rows without
correlations. If a row (What)
is completely empty, then we are missing a
How. This might be a
clerical error or worse; it might be that we can’t fulfill the
What.
- Columns
without correlations. If a column (How)
doesn’t have a correlation, again, it might be a clerical error. But
if it is not, then do we need that
How?
- Are we
missing any Whats or
Hows? In the process of
creating this first house, you probably will discover some
additional customer requirements. If this happens, add some rows.
SnapSheets XL makes adding rows and columns easy – and with no loss of
data.
Step #7: Pareto Results
SnapSheets XL will create
a Pareto of the Raw Scores for us. The resulting Pareto for our example
is below.
Many people are
tempted to refer to this as the “Answer” resulting from QFD. This
perspective is definitely not correct and/or greatly reduces the benefit
of QFD. This leads to
another QFD Key.
QFD Key #6- The entire matrix and the journey are the deliverable from a QFD. If
we had not gone through the QFD process, I wouldn’t have considered
making a pre-departure checklist, taking the boat, or leaving prior to
10am with DVDs for the Kids. Granted, given the Pareto we definitely
don’t want to forget to make the checklist. However, the entire house,
Whats,
Hows, roof, correlations,
Pareto, and the journey are all the deliverable or “answer” from
the process. We have a much better understanding of our market segment
and what will lead to a successful vacation.
Step #8: Move to HOQ #2 (as required)
In some cases we
might need to take a How or
combination of Hows and
break them down further. Take for example the requirement “Cost <
$1,000”. Sounds great, but how do we make this
How happen? That is the goal
of the next house and another article. The general approach is to start
a new HOQ, making the How
from House #1 the What in in
House #1.
I hope that this
has helped you understand the power of QFD. We believe that QFD is
exceptionally important any time you are designing a product, creating a
new process, or starting a project. To take the complexity out of
software usage, we created SnapSheets XL which allows you to set up and modify
QFD houses with little effort.
As a result, you can focus your time and energy on the
process instead of the
software.
About SnapSheets XL
SnapSheets XL is an
easy-to-use Excel add-in which makes creating and changing houses of
quality easy for everyone. For more information about SnapSheets XL, please
visit http://www.sigmazone.com/SnapSheetsXL.htm.
About SigmaZone.com
SigmaZone.com is a
leading provider of statistical tools, training, and consulting, serving
businesses across diverse industries since our inception in 1992. Our
solutions have delivered business results, return on investment, and
quality improvements in thousands of companies around the world.
By the way, you
might think I never actually used QFD or took this vacation. Wrong.
While I did change a few of the numbers (my budget goal was a
little higher than $1,000) I did take my family to the Florida Keys. An
added note: If your kids like animals, I highly recommend the Turtle
Hospital on Marathon Key (http://www.turtlehospital.org/).
The only way to see the turtles is to call ahead and make a reservation
for one of their tours.
Theater of the Sea
(www.theaterofthesea.com)
is also enjoyable; however, I would plan on a half day as opposed to the
full day previously mentioned.
Finally, the
fishing, boating, and water sports are always excellent. The water is
extremely flat in the keys. The typical wave that forms next to land is
practically non-existent, which makes boating on the ocean much less
rough than in most other locations.
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