SOFTWARE QUALITY FUNCTION DEPLOYMENT - Software Design for Six-Sigma: A Roadmap for Excellence - page 315

Critical to
satisfactions
(CTSs) Technical
Specifications

Design
parameters

High-Level
Functional
requirements
(FRs)

Requirements Process variables

(PVs) Procedures

(DPs) Methods
Tools

QFD Phase 1 QFD Phase II QFD Phase III QFD Phase IV

FIGURE 12.2 QFD 4 phases I/O relationship.

needs throughout the phases of the design development. The QFD methodology is
deployed through a four-phase sequence shown in Figure 12.3 The four planning
phases are:
Phase I—Critical to satisfaction planning—House 1
Phase II—functional requirements planning—House 2
Phase III—design parameters planning—House 3
Phase IV—process variable planning—House 4

These phases are aligned with axiomatic design mapping in Chapter 13. Each
of these phases will be covered in detail within this chapter. The input/output(I/O)
relationship among the phases is depicted in Figure 12.2.

CTSs
(Hows)

Critical to
Satisfaction

House
of
Quality
#1

Functional
Requirements (Hows)

House
of
Quality
#2

Prioritized CTSs

Design
Parameters (Hows)

House
of
Quality
#3

Prioritized Functional
Requirements

Critical to Process
Variables (Hows)

House
of
Quality
#4

Prioritized Design
Parameters

Prioritized Process
Controls

FIGURE 12.3 The four phases of QFD.