Introduction

QFD is a Quality system [Mizuno and Akao 1994]. The task of QFD in the overall framework of Total Quality Management (TQM) is to ensure customer satisfaction (see Figure 24.1) [Zultner 1993]. In order to achieve, or leverage, customer satisfaction, it is necessary to deliver and explain value to customers. To do this requires that the product/service be designed with value and produced with value. In order to develop such value into the product, we must start by discovering what value is for the customers we are trying to satisfy. We must understand from the customer's point of view what is valuable to them.

Figure 24.1. QFD as a quality system.

Definition of Value

There are only four sources of value for customers of software, and software-intensive products and services [Zultner 1996].

1. Solve problems. A problem is a current, negative situation. If we can minimize, or even eliminate, a customer's problem with a solution we provide, then we have delivered value proportional to the magnitude of the problem.

2. Seize opportunities. An opportunity is a future, positive situation. If we can advance, or even maximize, a customer's achieving an opportunity with a solution we provide, then we have delivered value proportional to the magnitude of the opportunity.

3. Look good. Customers want to look good to significant others. If we can significantly improve a customer's chances of impressing whomever they want to impress, with a solution we provide, then we have delivered value proportional to the importance of the impression to the customer.

4. Feel good. Customers want to feel good about themselves, their work, and their lives. If we can significantly improve a customer's feelings of confidence and satisfaction, with a solution we provide, then we have delivered value proportional to the level of the customer's feelings.

Any product, service, or software that does not address at least one of the preceding sources of value is valueless to customers. So how can we find the four sources of value for our own customers?

To satisfy customers today (so that they choose our product) and tomorrow (so that they are loyal to us) we must deliver value to them. To do this we must design and produce products and services that meet customer needs better than any other competitor. QFD ensures this during development.

Why Not Ask?

The most direct way to get answers from customers is to ask them. But they won't be able to tell us all of their requirements. The Kano model (see Figure 24.2) tells us that we are likely to miss whole classes of requirements [Kano et al. 1984]. The basic types of requirements are as follows:

• Expected requirements. These requirements can dissatisfy if not fulfilled, but do not satisfy if fulfilled. Most customers won't even mention theseunless you don't meet them, in which case they will be very vocal about what's missing.

• Normal requirements. These requirements can dissatisfy if not fulfilled, or satisfy if fulfilled. Most customers will mention thesebut only the ones they think of. Even with trained interviewers, it is difficult to reach as high as 80 percent discovery of these requirements.

• Exciting requirements. These requirements can satisfy if fulfilled, but don't dissatisfy if not fulfilled. Most customers won't mention these, because they haven't seen them before. If you meet these needs, customers will be very vocal about how much they like them.

  Figure 24.2. The Kano model.

  

So requirements differ in their effect upon customer satisfaction. And we won't get a complete set of requirements, because customers have no systematic way to sweep through their requirements space and download it to us. Yet we still must satisfy our customers!

Unprecedented Products

If we cannot rely on customers to tell us all their requirements, even for familiar products, what can we do for unprecedented products? For products that customers have never experienced before?

CUSTOMER NEEDS: Solution-independent benefits that customers desire to possess.