The House of Quality by John R. Hauser and Don Clausing Harvard Business Review Reprint
Design is a team effort, but how do marketing and engineering talk to each other? Digital Equipment, Hewlett-Packard, AT&T, and ITT are getting started with it. Ford and General Motors use it – at Ford alone there are more than 50 applications. The “house of quality,” the basic design tool of the management approach known as quality function deployment (QFD), originated in 1972 at Mitsubishi’s Kobe shipyard site. Toyota and its suppliers then developed it in numerous ways.
The house of quality has been used successfully by Japanese manufacturers of consumer electronics, home appliances, clothing, integrated circuits, synthetic rubber, construction equipment, and agricultural engines. Japanese designers use it for services like swimming schools and retail outlets and even for planning apartment layouts. A set of planning and communication routines, quality function deployment focuses and coordinates skills within an organization, first to design, then to manufacture and market goods that cus HARVARD BUSINESS REVIEW May-June 1988 tomers want to purchase and will continue to purchase.
The foundation of the house f quality is the belief that products should be designed to reflect customers’ desires and tastes – so marketing people, design engineers, and manufacturing staff must work closely together from the time a product is first conceived. The house of quality is a kind of conceptual map that provides the means for interfunctional planning and communications. People with different John R. Hauser, at the Harvard Business School as a Marvin Bower Sloan School of Management. He is the author, with Glen L. Urban, of Design & Marketing of New Products (Prentice-Hall, 1980).
Don Clausing is Bernard M. Gordon Adjunct Professor of Engineering Innovation and Practice at MIT. Previously he worked for Xerox Corporation. He introduced QFD to Ford and its supplier companies in 1984. Copyright 1988 by the Presidents and Fellows of Harvard College. All rights reserved.
HOUSE OF QUALITY
What’s So Hard About Design David Garvin points out that there are many dimensions to what a consumer means by quality and that it is a major challenge to design products that satisfy all of these at once. l Strategic quality management means more than avoiding repairs for consumers.
It means that companies learn from customer experience and econcile what they want with what engineers can reasonably build. Before the industrial revolution, producers were close to their customers. Marketing, engineering, and manufacturing were integrated – in the same individual. If a knight wanted armor, he talked directly to the armorer, who translated the knight’s desires into a product. The two might discuss the material – plate rather than chain armor – and details like fluted surfaces for greater bending strength. Then the armorer would design the production process.
For strength – who knows why? – he cooled the steel plates in the urine of a black goat. As for a production plan, he arose with the cock’s crow to light the forge fire so that it would be hot enough by midday. Todays fiefdoms are mainly inside corporations. Marketing people have their domain, engineers theirs. Customer surveys will find their way onto designers’ desks, and R&D plans reach manufacturing engineers. But usually, managerial functions remain disconnected, producing a costly and demor- alizing environment in which product quality and the quality of the production process itself suffer.
Top executives are learning that the use of interfunctional teams benefits design. But f top management could get marketing, designing, and manufacturing executives to sit down together, what should these people talk about? How could they get their meeting off the ground? This is where the house of quality comes in. Consider the location of an emergency brake lever in one American sporty car. Placing it on the guaranteed that women in skirts could not get in and out gracefully. Even if EXHIBIT II Japanese automaker with QFD made fewer changes than U. S. company without QFD U. S. ompany Design changes problems and responsibilities can thrash out design priorities while referring to patterns of evidence on the house’s grid. Japanese company of total Japanese changes complete 20-24 Months 14_17 1-3 +3 Months Job #1 Months EXHIBIT I Startup and preproduction costs at Toyota Auto Body before and after QFD January 1977 pre QED April 1984 post QED (39% of pre QFD costs) Preproduction costs Startup costs Source for Exhibits I and II: Lawrence P. Sullivan, “Quality Function Deployment,” Reprinted by permission. the system were to last a lifetime, would it satisfy customers?
In contrast, Toyota improved its rust prevention record from one of the worst in the world to one of the best by coordinating design and production decisions to focus on this customer oncern. Using the house of quality, designers broke down “body durability’ into 53 items covering everything from climate to modes of operation. They obtained customer evaluations and ran experiments on nearly every detail of production, from pump operation to temperature control and coating composition. Decisions on sheet metal details, coating materials, and baking temperatures were all focused on those aspects of rust prevention most important to customers. . David A. Garvin, “Competing on the Eight Dimensions of Quality,” HBR November- December 1987, p. 101 . 4 HARVARD BUSINESS REVIEW Today, with marketing tech EXHIBIT III iques so much more sophisticated than ever before, compacustomer attributes and bundles of CAS nies can measure, track, and for a car door compare customers’ perceptions PRIMARY SECONDARY TERTIARY of products with remarkable acEasy to close from outside curacy; all companies have opStays open on a hill Easy to open from outside EASY TO OPEN portunities to compete on quali AND CLOSE DOOR Doesnt kick back ty.
And costs certainly Justify an Easy to close from inside emphasis on quality design. By Easy to open from inside looking first at customer needs, Doesnt leak in rain then designing across corporate No road noise and use Doesnt leak in car wash functions, manufacturers can rel SOLATlON No wind noise duce prelaunch time and afterDoesnt drip water or snow when open Doesnt rattle launch tinkering. Exhibit I compares startup and Soft, comfortable ARM REST In right position preproduction costs at Toyota Auto Body 1977, before QFD, Material wont fade INTERIOR TRIM Attractive (nonplastic look) to those costs in 1984, when QFD was well under way.
House of CLEAN Good appearance Easy to clean No grease from door quality meetings early on reduced costs by more than 60%. Uniform gaps between matching panels Exhibit II reinforces this evidence by comparing the number f design changes at a Japanese auto manufacturer noise. ” Some Japanese companies simply place using QFD with changes at a U. S. automaker. The their products in public areas and encourage potenJapanese design was essentially frozen before the tial customers to examine them, while design team first car came off the assembly line, while the U. S. embers listen and note what people say. Usually, however, more formal market research is called for, company was still revamping months later. via focus groups, in-depth qualitative interviews, and other techniques. Building the House CAS are often grouped into bundles of attributes hat represent an overall customer concern, like There is nothing mysterious about the house of “open-close” or “isolation. ” The Toyota rustquality. There is nothing particularly difficult prevention study used eight levels of bundles to get from the total car down to the car body.
Usually the used to its conventions. Eventually one’s eye can project team groups CAS by consensus, but some bounce knowingly around the house as it would over a road-map or a navigation chart. We have seen companies are experimenting with state-of-the-art research techniques that derive groupings directly some applications that started with more than 100 rom customers’ responses (and thus avoid argucustomer requirements and more than 130 engiments in team meetings). neering considerations.
A fraction of one subchart, CAS are generally reproduced in the customers’ in this case for the door of an automobile, illusown words. Experienced users of the house of qualitrates the house’s basic concept well. We’ve reproty try to preserve customers’ phrases and even duced this subchart portion in the illustration clich?©s – knowing that they will be translated si”House of Quality,” and we’ll discuss each section multaneously by product planners, design engistep-by-step. eers, manufacturing engineers, and salespeople. Of course, this raises the problem of interpretation: What do customers want?
The house of quality What does a customer really mean by “quiet” or begins with the customer, whose requirements are “easy’? Still, designers’ words and inferences may called customer attributes (CAs) – phrases cuscorrespond even less to customers’ actual views tomers use to describe products and product charand can therefore mislead teams into tackling probacteristics (see Exhibit Ill). We’ve listed a few here; lems customers consider unimportant. a typical application would have 30 to 100 CAs. A Not all customers are end users, by the way.
CAS car door is “easy to close” or “stays open on a hill”; can include the demands of regulators (“safe in a “doesn’t leak in rain” or allows “no (or little) road HARVARD BUSINESS REVIEW 5 EXHIBIT Relative-importance weights of customer attributes BUNDLES RELATIVE IMPORTANCE AND CLOSE DOOR Easy to close from outside Stays open on a hill 7 ISOLATION Doesn’t leak in rain 3 2 A complete list totals 100% side collision”), the needs of retailers (“easy to display’), the requirements of vendors (“satisfy assembly and service organizations”), and so forth. Are all preferences qually important?
Imagine a good door, one that is easy to close and has power windows that operate quickly. There is a problem, however. Rapid operation calls for a bigger motor, which makes the door heavier and, possibly, harder to close. Sometimes a creative solution can be found that satisfies all needs. Usually, however, designers have to trade off one benefit against another. To bring the customer’s voice to such deliberations, house of quality measures the relative importance to the customer of all CAs. Weightings are based on team members’ direct experience with customers or on surveys.
Some innovative usinesses are using statistical techniques that allow customers to state their preferences with respect to existing and hypothetical products. Other companies use “revealed preference techniques,” which Judge consumer tastes by their actions as well as by their words – an approach that is more expensive and difficult to perform but yields more accurate answers. (Consumers say that avoiding sugar in cereals is important, but do their actions reflect their claims? ) Weightings are displayed in the house next to list totaling 100% (see Exhibit ‘V).
Will delivering perceived needs yield a competitive advantage? Companies that want o match or exceed their competition must first know where they stand relative to it. So on the right side of the house, opposite the CAs, we list customer evaluations of competitive cars matched to “our own” (see Exhibit V). Ideally, these evaluations are based on scientific surveys of customers. If various customer segments 6 evaluate products differently – luxury vs. economy car buyers, for example – product-planning team members get assessments for each segment.
Comparison with the competition, of course, can identify opportunities for improvement. Take our car door, for example. With respect to “stays open on hill,” every car is weak, so we could gain an advantage here. But if we looked at “no road noise” for the same automobiles, we would see that we already have an advantage, which is important to maintain. Marketing professionals will recognize the righthand side of Exhibit V as a “perceptual map. ” Perceptual maps based on bundles of CAS are often used to identify strategic positioning of a product or product line.
This section of the house of quality provides a natural link from product concept to a company’s strategic vision. How can we change the product? The marketing domain tells us what to do, the engineering domain ells us how to do it. Now we need to describe the product in the language of the engineer. Along the top of the house of quality, the design team lists those engineering characteristics (ECs) that are likely to affect one or more of the customer attributes (see Exhibit VI). The negative sign on “energy to close door” means engineers hope to reduce the energy required.
If a standard engineering characteristic affects no CA, it may be redundant to the EC list on the house, or the team may have missed a customer attribute. A CA unaffected by any EC, on the other hand, presents opportunities to expand a ar’s physical properties. Any EC may affect more than one CA. The resistance of the door seal affects three of the four customer attributes shown in Exhibit VI – and others shown later. Engineering characteristics should describe the product in measurable terms and should directly affect customer perceptions.
The weight of the door will be felt by the customer and is therefore a relevant EC. By contrast, the thickness of the sheet metal is a part characteristic that the customer is only by influencing the weight of the door and other engineering characteristics, like “resistance to deformation in a crash. ” In many Japanese projects, the interfunctional team begins with the CAS and generates measurable characteristics for each, like foot-pounds of energy required to close the door. Teams should avoid ambiguity in interpretation of ECS or hasty Justification of current quality control measurement practices.
This is a time for systematic, patient analysis of each characteristic, for brainstorming. Vagueness will eventually yield indifference to things customers need. Characteristics that are trivial will make the team lose sight of the overall design and stifle creativity. EXHIBIT V Customers’ evaluations of competitive products CUSTOMER ATTRIBUTES Worst 1 CUSTOMER PERCEPTIONS 5 Best How much do engineers influEASY TO OPEN Easy to close from outside 7 AND CLOSE ence customer-perceived qualiDOOR ties?
The interfunctional team now fills in the body of the house, the “relationship matrix,” indicating how much each engineering characteristic affects each customer OUR CAR DOOR attribute. The team seeks consenCOMPETlTOR A’S sus on these evaluations, basing COMPETITOR B’S them on expert engineering experience, customer responses, and tabulated data from statistical studies or controlled experiments. course, there might be an entirely new mechanism The team uses numbers or symbols to establish that improves all relevant CAs. Engineering is crethe strength of these relationships (see Exhibit VI’). tive solutions and a balancing of objectives. Any symbols will do; the idea is to choose those The house of qualitys distinctive roof matrix that work best. Some teams use red symbols for rehelps engineers specify the various engineering fealationships based on experiments and statistics and tures that have to be improved collaterally (see Expencil marks for relationships based on judgment hibit ‘X). To improve the window motor, you may or intuition. Others use numbers from statistical ave to improve the hinges, weather stripping, and studies.
In our house, we use check marks for posia range of other ECs. tive and crosses for negative relationships. Sometimes one targeted feature impairs so many Once the team has identified the voice of the cusothers that the team decides to leave it alone. The tomer and linked it to engineering characteristics, roof matrix also facilitates necessary engineering it adds objective measures at the bottom of the trade-offs. The foot-pounds of energy needed to house beneath the ECS to which they pertain (see close the door, for example, are shown in negative Exhibit VI”).
When objective measures are known, relation to “door seal resistance” and “road noise the team can eventually move to establish target reduction. ” In many ways, the roof contains the values – ideal new measures for each EC in a remost critical information for engineers because designed product. If the team did its homework they use it to balance the trade-offs when addresswhen it first identified the ECs, tests to measure ing customer benefits. benchmark values should be easy to complete. Enlncidentally, we have been talking so far about gineers determine the relevant units of measurethe basics, but design