Functional

The product must provide suitable features to satisfy the needs and desires of the intended users. A product with a large number of features is not guaranteed to be functional!

Usable

Easy to operate products are pleasurable and satisfying to use, while those that place unnecessarily high demands on the user will cause frustration for many people and exclude some altogether. Frustration with, or inability to use, a product can lead to a negative brand image. In the extreme, prolonged difficulties with poorly designed everyday products can even convince people that they are no longer able to lead an independent life.

Desirable

A product may be desirable for many reasons, including being aesthetically striking or pleasant to touch, conferring social status, or providing a positive impact on quality of life.

Viable

The business success of a product can be measured by its profitability. This typically results from having a product that is functional, usable, and desirable, and which is delivered to the market at the right time and at the right cost.