Product Design and Development – Chapter 4


Objectives of the Chapter:

1)                  To set the development focus on the customer

2)                  To establish a method to identify and sort out the customer needs


What is a Customer need? 

            Customer need:  “any attribute of a potential product that is desired by the customer”


A 5 step process


Step 1) Determining Customer Needs – collecting the raw data

How do we find out what the customer needs?

            Ask the customers.  How do you ask them?

a)                  Interviews with single customers

b)                 Focus groups of 8-12 customers

c)                  Written surveys


What is the best way and why? 

-                     Interviews are most cost effective per information gained (see Ex. 4-4, p.64)

-                     Surveys are not real helpful for initial needs, but may be useful later on to refine information.


Who do you ask?  Who is the “customer”?

·        Lead users – people who use the product frequently and are more likely to experience needs well in advance of the typical user.  Potential information includes 1)  Emerging needs to leapfrog the competition  2)  Suggested solutions

·        Regular users

·        Retailer who sells the product

·        Service/maintenance personnel


How many people do you interview?

·        Ideally until you cease to identify new needs (typically 10-50 hours of investigation)


How do you interview a customer?

·        Prepare questions in advance (see p 66 for a common list of questions)

·        Use the questions as needed.  Don’t worry if you get off track but the customer is still providing useful information.  Go with the flow.

·        Use stimuli and props.  Like what?  Existing products, preliminary concepts (end of interview)

·        Do not introduce bias.  If the customer starts to focus on a specific design or technology, try to move away from the focus to an understanding of why they have that focus.  What is the need they are communicating?

·        Have the customer demonstrate use of the product (if possible)

·        Be alert for surprises. 

·        Watch for nonverbal information. (75% of communication is nonverbal)  What gets the customer excited? Frustrated? Etc. 

Example:  Mechanical pencil:  Who is a lead user?  Who are other customers?  What props do you provide?  What are potential bias’s? (clicker, shape, refill method…)  What nonverbal information might you get? (holding pencil, facial expressions, tone of voice, …)


How do you document the interview?

Video (best – why?), audio, written notes, still photography


How do you process the data?  See Exhibit 4-6 on page 68.  Build a summary table:

Basic interview info at the top.  Who interviewed, interviewers, date, location, etc.



Customer Statement

Interpreted Need





Step 2 - Interpreting the Customer Raw Data


How do we guarantee that all team members are consistent in their interpretation of customer needs?  (Use a structured interpretation method)


Interpretation guidelines:

1)      Express what the product has to do, not how to do it.  What does this mean and why do we do it this way?  Example:  The storage tube for pencil leads needs to hold at least 10 leads.  Is that a has to or how to statement.  What is a better statement?

2)      Do not add or subtract detail from the customer responses.  (Avoid losing information or assuming information)

3)      Phrase needs in a positive manner:  “The product can do…”  Why do we do this??  (sets an easier way to measure.  How do you measure what something can’t do?  (The pencil eraser can’t be hard to use)

4)      Express needs as product attributes:  The need belongs to the product (A person is comfortable writing with the pencil becomes… The pencil is comfortable to use)

5)      Avoids the words must and should.  Why???  What is the difference between these words?  Where do we set priorities of “must” vs “should” characteristics?  These indicate a relative priority that may not exist.


Step 3 – Organize the Needs into a Hierarchy


How many different customer statements would you expect to gather if you were to interview, say 20 people?  100?, 200? 


Does each statement represent a unique customer need? 

How many unique needs exist? 

How do we identify the primary customer needs from so many?


The text gives a good, systematic, 6-step process:

1.   Write each need statement on a separate card or self stick note.  (or print them on a computer page and cut them apart)

2.   Eliminate redundant statements (identical in meaning)

3.   Group the remaining cards by similarity.  For example, let’s try the backpack again.  (solicit 10 statements, put them in good format)

      Which ones express a similar need?  Group these.

4.   Label each group with a more general need.  What statement best expresses the common need of the grouped cards?

5.   If necessary (if more than 20 groups) create supergroups by combining again.

6.   Review the results and edit as needed.


Final result:  A set of primary customer needs (probably 10-20, depending on the size of the project).  Each primary need has a group of secondary needs associated with it.  These secondary needs help better define the primary need.


Step 4:  Establish the Relative Importance of the Needs


How do we determine which need is more important?  Why do we need to know which are the more important needs (resource allocation, design tradeoffs, etc.)?


Two possible methods:


1)   Group consensus based on interactions with customer – Quick, but at the sacrifice of accuracy.


2)   Customer surveys – Using the list of secondary needs.  Usually best to rate on a scale (say 1-5).  Also allows opportunity for customer to identify unique or unexpected needs on the list (WOW features that might increase the product’s appeal)  Note Exhibits 4-8 and 4-9 in text.


Step 5: Reflect on the Results and the Process


-                     Did we interview enough and the right customers?

-                     Did we go beyond the capability of existing products in searching for needs?  (i.e.  were the responses limited by knowledge of products?)

-                     Do we need to understand any areas better? (product specs will help determine this!)

-                     Which customers are available for follow-up participation?

-                     Any surprises?  Why or why not? (should there be any???)

-                     What could we do better in the process?