Design-build, on the other hand, can demand that the design-builder offer a firm, fixed price for a project whose scope is defined by a set of performance criteria within a specified period of time (Molenaar and Gransberg 2001). Therefore, the variable leg in the DB stool is the details of design. This puts the design-builder in a position where the details of design, and hence the resultant level of quality, are constrained by both the budget and the schedule. In other words, the design-builder must design to cost and schedule. As a result, it is extremely important to both the owner and the design-builder that the requirements for quality be clearly communicated in the Request for Proposal (RFP) so that the resultant proposals will be as responsive to the owner's needs as the cost, technical, and time constraints of the project allow.