Abstract :
A central task in design is deciding what artifact will best satisfy the client´s needs, whether that requires creating an artifact or choosing from existing alternatives. A design space identifies and organizes the decisions that must be made, together with the alternatives for those decisions, thereby providing guidance for creating artifacts or a framework for comparing them. The Studying Professional Software Design workshop studied three pairs of professional software designers sketching designs for a traffic signal simulator. A discussion of the design space for the simulation task shows how this design space enables comparison of the designs. It also illustrates the benefits of explicitly considering the design space during design and the risks of failing to do so.