A constraint-satisfaction approach to studying the management of multiple objectives in design problem-solving

How professional and novice designers manage multiple objectives through constraint satisfaction was studied. An objective is defined as a network of constraints; a constraint is characterized as related to a source (internal or external) and an addressee (e.g., client or user). It has been shown that designers favour objectives related to external constraint (e.g., data from the task) and to the client. Generally, client and external constraints are identical. To study the management of multiple objectives, fifteen web site designers were instructed to design a site according to user's objectives or client's objectives. Our results indicate that the validity status allocated to constraints is more determined by the status of the addressee than by the status of the source, whatever the objective condition that must be satisfied. Possible methodological generalizations are discussed.