Quality Function Deployment - QFD is a method of customer-oriented product development, or rather customer-oriented quality management. In a nutshell, it is about converting customer wishes into concrete product features.
Customer wishes can be ascertained via the questioning of individual customers during personal interviews, through focus group discussions, and/or by using the Kano methodOpens in new window.
After finding out customer standards it is then necessary to engage in carrying these wishes over into concrete features. QFD furthers the attaining of this goal.
The origin of QFD can be traced back to Japan in the late sixties, where the Mitsubishi heavy industries shipyard in Kobe conceptually developed the procedure, and made it public for the first time (Akao, 1992, p. 13).
The application of QFD is not limited to the investment and consumer goods sectors, as it can also be used in the service performance area (e.g., banks, commercial enterprises). The method of QFD consists of four planning phases:
Conversion of customer wishes into actual construction features: In this phase the idea is to take the customer wishes that have been discovered and transform them into product features.
Conversion of construction features into plans for assembly and components: Here decisions are made here as to how to assemble the product features discussed in the first phase.
Conversion of assemblies and components into process plans: The decided upon assemblies and components are assigned to the processes which will contribute to their realization.
Conversion of process plans to work plans: In the last phase of product planning the processes are converted to concrete work and checking instructions, which compliment and add detail to the process plans.
Each of these planning phases is supported and visualized via so-called House of Quality (see Figure X-1). This endeavor assures the universal conversion of customer wishes all the way to actualized work instructions, where the benefit of each operational stage is made significant against a background of market standards.
This offers the advantage of encouraging the productive cooperation of various organizational areas (marketing, sales, production), and of obtaining the varying points of view and professional competencies involved.
In its structure, the House of Quality consists of ten areas. These areas will be described below:
In the first area, the customer standards (customer wishes) are entered. Moreover, this area includes the importance of the standards from the point of view of the customer. The evaluations of each customer standard are normally presented in percentage values, whereby all evaluations add up to 100 percent.
The second area describes the technical construction features, which have an influence on the customer standards.
In the third area, it is established how much each technical construction feature influences the customer standards (relationship matrix). The assessment is based on experiences, customer reactions, and/or appropriate data, which come from statistical studies or from experiments.
The fourth area deals with the question, how much would the alteration of a construction feature influence the other construction features (roof matrix)? It should become clear which problems arise in realizing the customer standards, and where technical solutions mutually compliment or hinder each other. If it works, for example, to reduce the energy expenditure in closing the door (customer standard of easy to close from outside), then this hinders the improvement of resistance on a ten degree incline (customer standard of door not slamming closed on hil).
The fifth area is comparison with the competition, whereby the comparison is from the customer’s perspective (Benchmarking). Ideally, the assessment will be based on well-founded customer surveys.
In the sixth area, criteria are established for the assessment of technical construction features, and for the comparison of the company’s own product with the competition’s products, on the basis of these criteria.
The seventh area is an assessment with regard to the technical difficulty of realizing an improvement to the feature in question. The assessment of the difficulty proceeds according to a numerical scale (e.g. from 1 = no problem, to 6 = not attainable).
An exclusivity internal assessment of technical attainability can lead to over hasty rejection of solutions, which from a market point of view would have been necessary. For this reason, in this area it is advisable to objectify, e.g., bring in external and independent experts.
The eight area is concerned with the significance of individual construction features. The assumed significance proceeds according to a background of information with regard to customer standards, customer importance, customer assessment (benchmarking), and technical difficulty. A determination like this is not simple, but on the basis of the available information it is justifiable and comprehensible.
In the ninth area there is an assessment of the proportionate cost of the current construction features. It makes sense, in addition to the usual finding out of the proportionate cost, also to consider what the customer is prepared to pay for a particular construction feature. The relevant information can be gathered via well-founded surveys and/or via conjoint measurement. In such a course of action, there also arises a connection between QFD and target costing.
The tenth area documents the targets with regard to the individual construction features.
On the basis of the assumed significance of the individual construction features, the prevailing proportionate cost, and customer assessment, specific and measurable guidelines are determined. If for example, the product standard with regard to driving noise is observed, one can see that the supplier being studied has a lower value here than the competition. The consequence is that as a guideline an objective quality criterion of ‘9 db’ will be maintained.
Figure X-2: The Four Phases of QFD
After creating a House of Quality for converting customer standards to construction features, the conversion of the next phase follows according to a new, appropriate House of Quality (see Figure X-2). For example, if the guideline indicates an adjustment of a compressor to a value of 3.6 (work instruction in Phase 4), this signifies a speed of 100 rotations per minute.
In this connection, the press produces (process sealing press in phase 3) a weather proofing sealing bulge of even diameter (assembly sealing in phase 2). This sealing guarantees a good insulation and raises the door closing effort only by an inconsequential degree (construction feature in phase 1). These construction features fulfill the expectations of the customer regarding a dry and quiet car, with doors that are easy to close (Hauser & Clausing, 1998, S. 79).
Figure X-1: The QFD House of Quality Diagram courtesy of NPD SolutionsOpens in new window
Figure X-2: The Four Phases of QFD
