4. Defining and prioritizing needs

This is a key phase in terms of the notion of "value". It's based on listening to the customer and understanding the market. Be careful not to confuse needs and functions: a function is the way in which a product satisfies a need.

• Tool

  Determine needs (or expectations). Identify the user(s) and the people who will interact with the product. Identify, characterize and, wherever possible, quantify what these people will perceive and "judge" the product on. You can use the Spider Sheet (Tool