Kano Model & Critical-to-quality Tree

Developed in the 80's by Professor Noriaki Kano, the Kano model is based on the concepts of customer quality and provides a simple ranking scheme which distinguishes between essential and differentiating attributes. The model is a powerful way of visualizing product characteristics and stimulating debate within the design team. Kano also produced a rigorous methodology for mapping consumer responses into the model.

Product characteristics can be classified as:

Threshold / Basic attributes - Attributes which must be present in order for the product to be successful, and can be viewed as a 'price of entry'. However, the customer will remain neutral towards the product even with improved execution of these threshold and basic attributes.

One dimensional attributes (Performance / Linear) - These characteristics are directly correlated to customer satisfaction. Increased functionality or quality of execution will result in increased customer satisfaction. Conversely, decreased functionality results in greater dissatisfaction. Product price is often related to these attributes.

Attractive attributes (Exciters / Delighters) - Customers receive great satisfaction from a feature and are willing to pay a price premium. However, satisfaction will not decrease (below neutral) if the product lacks the feature. These features are often unexpected by customers and can be difficult to establish as needs during initial design. They are sometimes called unknown or latent needs.

Next, we organize customer needs into a Critical-To-Quality tree

The purpose of Critical-To-Quality trees is to convert customer needs/wants to measurable requirements for the business to implement.

For example: A retail merchant was receiving a significant number of complaints regarding their homeowner warranty policies from their customers. By analyzing customer survey data and developing the CTQ tree, the business was able to identify critical-to-satisfaction requirements. These requirements became the focus for improving customer satisfaction. The business eliminated mandatory warranty visits and made all warranty visits optional. Eliminating mandatory visits satisfied the customers who thought there were too many visits and adding an extra optional visit satisfied customers who thought there were too few visits. Expanding the time frame for scheduling warranty visits from two weeks to three months eliminated the inconvenience for customers who had busy schedules and found the time frame difficult to manage.

The business took a general, difficult-to-measure need (to improve homeowner warranty satisfaction) and developed specific, measurable, and actionable requirements to drive improvements in customer satisfaction.