2. Organizing functions

It is important that the functions and constraints selected for the solution studied :

• are independent and non-redundant: study any goal/medium relationships between the various functions expressed, asking the "Why?" and "How?" questions for each one;

• are those of the solution under study and not of a larger whole or a component: use in the expression only elements directly related to the solution;

• are linked to their specific context: separate functions for different contexts: life-cycle stages, use situations, user categories...

A final inventory containing more than a dozen functions for a product will often be the sign of an incomplete organization: some expressed functions may be criteria of other functions (group them together), or...