When designing a product it is useful to know how much customers value various attributes of that product. This allows us to design the product most preferred by consumers within a limited budget. For instance, if we determine that consumers place a very high value on a long product warranty, then we might be more successful in offering a long warranty with fewer color options.

The basic idea behind conjoint analysis is, while it may be difficult to get consumers to accurately reveal their relative utilities for product attributes, it's easy to get them to state whether they prefer one product configuration to another. Given these rank preferences, you can use conjoint analysis to work backwards and determine the implied utility functions for the product attributes.