The Information Exchanges at Stage 3 comprise the design information that is coordinated including any Project Strategies or other Project Information. The aim of Stage 3 is to test the Concept Design further, including through the development of specifications and Cost Information. In some respects the challenges presented at Stage 3 will depend on how rigorous the lead designer’s strategic work has been at Stage 2. Increasingly shorter project timescales mean that the progression from a blank screen to a Concept Design must be rapid. A federated model comprises all of the 3D building information modelling models of the design team. The models are reviewed by the lead designer before they are uploaded to the common data environment. Cost exercises led by the lead designer at Stage 3 should help eliminate assumptions made at Stage 2, clarify the specification for all aspects of the design and allow a review of the contingency allowances.