The Concept of Utility-

The concept of utility has been developed as a common scale for evaluation of a product on a number of diverse dimensions such as cost, safety and ease-of-use. This scale is based on the personal preferences of the evaluator, and as such, is highly subjective. The utility of a product on a particular quality dimension measures the usefulness of that particular quality characteristics of the product in the opinion of the evaluator. Thus, the utility of a design on, say, the adaptability dimension is a measure of the contribution of the adaptability of the design to the overall usefulness of the product. The overall utility of a product is the sum of utilities of each of the quality dimensions