The House of Quality, or Quality Function Deployment (QFD), is a useful tool that Six Sigma Black Belt practitioners use during the Define phase of the DMAIC cycle of Six Sigma projects. The topic can be briefly discussed in Green Belt training or sometimes on online free Six Sigma courses. However, the House of Quality is one of the more advanced LEAN techniques. Let’s look at a practical example of how the House of Quality technique can be implemented.
House of Quality Steps
To build the house of quality, basic six steps are performed. House of Quality Steps are as follows:
- Identify what customer wants.
- Identify how the product will satisfy the customer. It refers to identifying specific product characteristics, features or attributes and showing how they will satisfy customer wants
- Identify relationships between how’s. A couple of questions, that are to be answered here: How do our how’s tie together? What is the relationship between our two or more how’s?
- Develop importance ratings. It refers to using the customer’s importance ratings and weights from the relationships in the matrix to compute our importance ratings.
- Evaluate competing products or services. The question to be answered here is: How well do competing products meet customer wants? This activity is completely based on research.
- Determine the desirable technical attributes. In this step, our performance and the competitor’s performance are determined and compared.
The basic graphic diagram for any House of Quality looks like this.
How to Make House of Quality? A House of Quality Example
Let us now begin with the actual process of generating a House of Quality for Pizza.
Identify what the customer wants
The main features that any customer desires in a pizza are:
- Good taste
- Low price
- Low fat and healthy
- Appetizing appearance
- Fresh and hot delivery
- Good texture
To build a House of Quality we need to deep-dive into the main features. This part of building a House of Quality is normally a group exercise that requires brainstorming.
- The first main feature is good taste. Taste is the first thing that a customer demands in any food item. The better the taste the more customers will demand it. So, it should taste fresh, hot and spicy all the time.
- The second main feature is low price. Price is the second most important factor according to the customers. The customer always tends to purchase food that tastes good at a low price. So, there shouldn’t be any compromise on taste while keeping the price as low as possible to meet the customer requirements.
- The third main feature is low fat and healthy. No one wants to get sick or become fat after eating something delicious. So, the pizza being sold to the customers should be low in fat and it should be part of a healthy diet for the customer. This is the key to winning the customer’s order.
- The fourth main feature is appetizing appearance. The pizza should look mouthwatering. It should look delicious, appetizing and spicy, even if the customer hasn’t yet tasted one.
- The fifth main feature is fresh and hot delivery. No one wants to have a stale pizza. Everyone wants a fresh and hot pizza, even if they’d ordered it home. Quick-n- Hot delivery should be maintained for all customers or else we’ll lose our customers.
- The sixth main feature is a good texture. Well, the texture is the lowest priority of customers. It is same as the appearance of pizza but it is affected by shape, size, the method of baking, and ingredients too. Good texture for each variety of pizza should be maintained.
To build our House of Quality we have to determine the importance ratings according to customer needs. We determine the importance ratings for our House of Quality on a scale of 1 to 6.
How will the product satisfy the customer’s wants
In this step of building a House of Quality, we have to reflect the customer’s desires and demands in relation to our company’s product. For our House of Quality, we have to consider those before we finally approve the making and cooking of our Hot-n-Spicy pizza. Our product would be able to provide these features to the customer:
- Delicious and fresh toppings (sausages, meat, bread slices etc.)
- Appropriate weight, size, shape, and thickness
- Low-fat eatables (less cheese and/or yeast)
- Optional eatables for taste and texture
- Pizza color
- Variety and density of toppings
To build a House of Quality we need to deep-dive into these features one-by-one.
Fresh and delicious toppings
The first feature is Delicious and Fresh toppings. It is a key material for pizza. Delicious and fresh topping would surely help customers’ winning orders.
Weight, size, thickness, and shape
The second feature is appropriate weight, size, thickness, and shape. These features of pizza are directly related to pizza price. The heavier the pizza, more it would cost etc. So, the pizzas should be available in different sizes and weights so that every customer would be able to purchase the one that they prefer. That is why we’re going to introduce Medium and Large size pizzas.
Our customers want a healthy pizza. So, we’re going to use those ingredients which are low in fat. Some ingredients are essential for the taste of pizza but they have a high fat-value. Hence, we will try to use them as little as possible.
Optional eatables are purely concerned with the taste and variety in pizzas. For providing great and delicious varieties in our pizzas, we will use different optional eatables to delight our customers. This factor is also concerned with price and texture.
For an appetizing appearance of a pizza, we would have to add some artificial colors to our pizza product. Additionally, these flavored colors also add spicy tastes to pizzas.
Density of toppings
The density of topping is directly concerned with the thickness and price of a pizza. To provide varieties of pizza, we will use a Low, Medium and High density of toppings.
Developing the HOWs for our House of Quality
Now, in the next step of building our House of Quality we will develop the “HOWs” or how will our product satisfy our customers for our House of Quality. For this purpose, we will again develop a table displaying how this will satisfy them.
Identify relations between our HOWs for our House of Quality
In this step of building our House of Quality, we will develop a relationship matrix between our ‘HOWs’. For example, in many cases, some ‘HOWs’ are related to one-another. Here’s a diagram showing an example of how HOWs can be related to each other when building our House of Quality.
Develop importance ratings
This step of building a House of Quality is quite difficult and takes longer to complete. To build a House of Quality we will first draw the relationship matrix between the “HOWS” and the “WANTS”. Then, we will determine the importance ratings for our final work to be started.
Have a look at the diagram below. This step of building a House of Quality is shown here in a simplified and explanatory way. Let’s have a quick example to understand the table and how it is important for building our House of Quality.
The customer want of good texture has a medium relationship with pizza color. Good texture has the customer importance rating of 1. According to the grid in our diagram, medium relationship i.e. the bold green circle has the importance rating of 3. So, simply multiply 3 by 1. That’s it! The answer for importance rating of pizza color is 3.
Evaluate competing products
In this step of building our House of Quality, we will compare the features of competing products of other companies. For example, two companies, Company A and Company B are competitors for our products. Hence, to build our House of Quality, we’ll first discuss and compare their pizzas to ours to get a more comprehensive and detailed report about our pizza.
Please have a look at the diagram below. On the left-hand side, we have customer wants. On the right-hand side, we’ve got Company A and Company B. According to our grid of G, F, and P, we have tried to evaluate our competitors’ pizza against customer wants.
Determine technical attributes
The last step in building a House of Quality is determining of technical attributes and checking our performance with respect to market products.
And here is our final and full House of Quality or Quality Function Deployment (QFD) diagram for Pizza.
Good luck building your own House of Quality in the Define phase of your Six Sigma project. Use this LEAN tool to identify exactly how to produce a product that will delight your customers.