Quality Function Deployment

Meeting customer needs is the ultimate goal of every product. After all, if they don’t think they need it, why would they buy it? However, identifying specific customer needs and weighing them against technical constraints can be difficult. Quality function deployment (QFD) is a method for doing this in a structured and collaborative way.

This glossary article defines what QFD is, the pros and cons of implementing it, and how to perform it.

What is Quality Function Deployment?

Quality function deployment is a group decision-making technique that incorporates the voice of the customer in the discussion surrounding the technical requirements of a product. You can also use a planning matrix to define customer requirements and establish how they weigh against a predetermined set of design constraints.

QFD allows product designers to think together while maintaining a focus on user demands. This ensures that your team stays better aligned and also that the design of your product satisfies the needs of the customer. As an added benefit, it keeps wild ideas from bloating the project or steering it off course.

Many quality function deployment applications also take competing products into account. Competitors are weighed against the same requirements that customers have declared as important to their buying decision. By doing this, QFD helps contextualize the design against the state of the market. When the strengths and weaknesses of the competition are revealed, opportunities to come out ahead will surface, too.

What is the History of Quality Function Deployment?

Yoji Akao, a Japanese planning specialist, invented quality function deployment in 1966 with the help of Mizuno Shigeru, a training content developer. After that, in 1972, Mitsubishi Heavy Industries built on the method by introducing the house of quality (HOQ), a planning matrix that has become synonymous with QFD.

After demonstrating a record of success, QFD gained popularity in Japan and drove the explosive growth in the sale of Japanese vehicles around the world during the 1970s. Inspired by this success, American car makers imported the model in the 1980s. This led to increased customer satisfaction, a rise in innovation, and an increase in domestic vehicle sales.

How Do You Perform Quality Function Deployment?

There are four distinct macro phases in quality function deployment: product definition, product development, process development, and process quality control.

Let’s look at what these steps involve in the following:

Product Definition

During this phase, gathering the voice of the customer is the main concern. You can pinpoint customer opinions in a myriad of ways: conducting interviews, hosting focus groups, or using any other related method.

After collecting sentiment, product stakeholders meet to discuss the findings from the data. They will then determine how customer sentiment translates into requirements or features.

At this stage, the team deliberates on how to best fill the house of quality, which we’ll cover in the following.

Filling in the House of Quality

Creating and filling the house of quality is a team activity where different team members are invited to collaborate. Everyone participating in deliberations is encouraged to provide input based on their area of expertise.

The five-step process to filling in the HOQ goes like this:

1. Fill Out Customer Demands and Ratings

First, enter the most important customer needs on the left side of the house of quality. Next to these, add how customers rated the importance of each need on a scale of 1 to 5. Finally, convert these ratings to percentages by dividing each rating against the sum of all customer ratings.

2. List Design Constraints

Next, go over each column and fill in the parameters that will affect the design of the product. These include considerations such as weight, cost of production, and speed. Above each, use ▲ or ▼ to indicate if more or less of the stated parameter is the desired outcome.

3. Determine the Correlation Between Different Constraints

After determining constraints, use the roof of the house of quality (also called the correlation matrix) to show the correlation between different constraints. Use + to show a positive correlation, - to show a negative correlation, and double them (++ or -) to show a stronger positive or negative correlation.

4. Weigh the Relationship Between Customer Demands and Design Constraints

Now, in the central matrix, determine how strongly each constraint affects each corresponding user demand. Use the following weighted symbols to do this:

Then, multiply each value against their corresponding customer rating percentages. Sum up the totals for each column to get the importance rating. Finally, convert these to percentages by dividing each rating against the sum of all importance ratings.

5. Show Competitor Research

Lastly, on the right side of the HOQ, show how customers rated competing products against their corresponding demands.

Product Development

Using the house of quality as a guide, the design team translates the prioritized product specifications into part and assembly features during this phase. This is also when design defines the functional requirements of the product.

Process Development

Using the results of the product development phase, the production team lays out the manufacturing and assembly processes needed to produce the finalized design.

Process Quality Control

Finally, the quality control team identifies the parameters that are critical to the product’s success. These parameters are what your team will use to develop tools, inspection procedures, and quality control tests with which to grade the product’s quality during production.

What are the Pros and Cons of Quality Function Deployment?

Like any decision-making technique, quality function deployment comes with its own set of pros and cons. Knowing what these are can therefore help you decide if QFD is right for your product, your approach to product management, and your organization as a whole.

Here’s a comparison of the benefits and the risks when using QFD as part of your product design process:

Pros

• It ensures that the product brought to market is something that customers want by taking their desires into account at the start of the design process.
• It assigns strategic priority to specific requirements of the product, communicates that priority across the company, and also guides designers throughout the product development process.
• Designer are encouraged to collaborate to identify the most important parameters to include in the design.
• It aligns the entire organization toward the goal of customer satisfaction, which, in turn, reduces internal competition motivated by differing priorities.
• It compares the design parameters of the product in development against competing products, so opportunities for competitive advantages are created.
• Development time and cost are reduced by keeping the team focused on common goals and reduces feature bloat.
• It prevents the creation of products that do not provide customers with any benefit and are, thus, unlikely to sell.

Cons

• It can result in tunnel vision on customer needs, which can therefore have negative repercussions if these same needs delay innovation or drive up product costs.
• Its implementation might be a seismic change for companies with established processes focused on cost reduction and profitability.
• It places a lot of trust in the results of a customer survey that can push an organization in the wrong direction if poorly designed and executed.
• It doesn’t account for changes in user wants and needs that may arise after the beginning of the design process.

Capture Customer Needs to Create Great Products

In conclusion, how your customers perceive your product decides how well it performs on the market. By using QFD, you can ensure that your product incorporates what customers want, and therefore increase its chance of success.