Conjoint Analysis is a market research technique that looks at how people make buying decisions and what they really value in products and services. Conjoint analysis helps answer questions like "Which should we do, build in more features, or bring our prices down?" or "Which of these changes will hurt our competitors most?"
The approach breaks a product or service down into it's constituent parts then tests combinations of the parts to determine what customers prefer.
more details at dobney.com a marketing research consultancy