Quality Function Deployment in Product Development

By A. Fernandes

Quality Function Deployment (QFD) is a tool that is sometimes referred to as the “voice of the customer,” or as the “house of quality.” This tool has been described as a process to ensure that the customers’ wants and needs are heard and translated into technical characteristics.

Developed by Japanese professors Shigeru Mizuno and Yoji Akao as a tool to design customer satisfaction into a product before it was developed, it was first used in 1971 by Mitsubishi Heavy industries in the design of oil tankers.  The Toyota Motor Group strongly influenced adoption of QFD in North America.  From 1977 to 1984, the company achieved a 61% reduction in product development costs and a 33% reduction in product development cycle time while virtually eliminating vehicle rust related warranty problems. Today, the tool is scarcely used largely due to the perception that a significant time and resource investment is required to thoroughly complete the exercise. 

With Siri at our beck and call, and society’s insatiable appetite for immediate information, developers are now able to rapidly collect guiding research.  Consumer sentiment, preference, ratings, pricing, and competitor positioning can all be collected and tabulated quickly.  Yet alone, the old data collection methods made efficient are insufficient in and of themselves.  An immediate accumulation of data does not guarantee you will properly identify and define your objectives. Ironically, these advancements have given an old tool new life. Historically, streamlining the collection of these data proved to be a manually labor intensive and time-consuming component of the QFD process.  As with many processes, technological advancements have alleviated the burden of collecting research necessary to populate QFD.

QFD provides a tried and tested format that can be used to house this information. More importantly, it translates this data from the qualitative abstract to quantitative targets with the goal of providing the consumer exactly what they need. QFD accomplishes this in several ways:

  • Systematically allows you to learn about your customer.
  • Ranks the wants and needs hierarchy.
  • Allows you to learn about your competition through benchmarking.
  • Sets target goals for products or service success.
  • Provides a tool for converting wants and needs into technical requirements.
  • Allows for feature cost/benefit evaluation and tradeoff.
  • Allows you to assess your performance relative to the competition.

House Construct

QFD consists of 6 general sections (Fig 1) sometimes referred to as rooms including:

  1. Consumer Requirements – a structured list of requirements derived from consumer research.
  • Planning Matrix/Customer Perception – Illustrates customer perceptions observed in market surveys and includes relative importance of customer requirements and competitor performance against those requirements.
  • Technical/Design Requirements – a structured set of relevant and measurable product characteristics.
  • Interrelationship Matrix – illustrates the QFD team’s perceptions for interrelationships between technical and consumer requirements.  Filling in this portion of the matrix involves discussions and consensus building within a development team.  The team must concentrate on key relationships and limit the number of requirements to only those that are highly rated by the consumer.
  • Technical Correlation Matrix – Used to illustrate negative and positive correlation to identify areas where technical requirements support or impede each other in the product design.
  • Prioritized Requirements, Technical Benchmarks and Technical Targets – This is the final output of the matrix and is a set of target values for each technical requirement to be met by the new design, which are linked back to the demands of the consumer.  It also is used to record priorities, measures of technical performance achieved by competitive products and illustrates the degree of difficulty involved in developing each requirement.

Fig 1.

Research

Research is the primary ingredient and is crucial to ensure that subsequent activities are worth the effort and add value to developer decision making. Developers must use all methods and avenues at their disposal to get at the heart of the consumer. Research types often include: 

  • One-on-one/exploratory Interviews customer interviews
  • Focus groups
  • In-context customer visits
  • Surveys
  • Usability tests
  • Social Listening
  • On-Site Activity (Via Web Analytics)
  • SWOT
  • Comment Boxes (Web)
  • Other Marketing Research Techniques & Tools

The output of good research is a well-developed hierarchy based on sound data. Force ranking consumer needs is an important step in establishing a foundation for characteristic weight, impact, and relationship scoring.  A misstep here, risks establishing proper technical targets. 

Performing research allows developers to interact with target consumers. These interactions formulate a product vision beyond functional requirements often escalating into anticipated design and aesthetic features. Ultimately, the success of any product or service is its desirability in the marketplace.  Social media along with ecommerce have shifted focus form a product oriented to a consumer-oriented design mindset.  Consumers expect omni-channel availability and store-to-door service. Equally important, they favor high-quality products that deliver superb product experience. Consumers no longer only vote with their feet, but also voice their opinions to a world audience that is socially listening intently.  It only takes the influence of one consumer to begin a positive or negative frenzy. Developers need to structure these vast amounts of data in a meaningful manner and be aware of how they can extract directional data.

Like defining a problem statement, data deciphering must be handled with care and certainty. It is upon this list of wants and needs that formulate a foundation upon which the balance of the house is constructed. Only in the identification, sorting, and organization of this information can we discover our roadmap to developing a product that hits the mark.

House Expandability

QFD requires proper planning prior to construction and can graduate from design, assembly, process, and quality control in sequentially separate but linked phases.  The phased approach illustrates how the output of each phase provides the input into the next phase. Using this graduating system allows a traceability chain that ties product performance back to the consumer. QFD does not mandate that all houses be constructed to realize the tool’s value. Therefore, developers should perform a cost-benefit analysis to assess each of the houses and their added value to resolve how far to carry out additional phases. 

QFD Goal

The final output of the matrix is a set of target values for each technical requirement to be met by the new design, which are linked back to the demands of the customer. QFD is truly a translation tool that often takes an obscure definition and translates it into a language that designers and engineers can use to develop products. Benefits of QFD include:

  • Creates a customer-driven environment
  • Reduces the cycle time for new products
  • Uses concurrent engineering methods
  • Reduces design to manufacture costs (fewer changes)
  • Increases communications through cross-functional teams
  • Creates data for proper documentation of engineering knowledge
  • Establishes priority requirements and improves quality.

The advancements in technology have truly given this old tool new life.