3. Characterize functions

Each function and constraint must be dimensioned by :

• criteria: characteristics or dimensions of the action verb and the elements cited ;

• acceptance levels for each criterion ;

• a level of flexibility for each dimensioning, depending on whether the acceptance level is required (F0), conditionally modifiable (F1) or flexible (F2);

• and/or an exchange rate, where the expected level of performance depends on the resources to be devoted to it.