It is rarely in anyone`s interest. These are all things that must be taken into account when determining the level of risk to be imposed on a contractor, although the magnitude of the risk depends heavily on the specific project. In addition, these two documents are the key to understanding how the JCT Design and Build contract works (including the latest DB 2016) and how the design risk is distributed between the contractor and the employer. In other words, the contractor owes the employer an obligation similar to that of an architect (e.g. B reasonable skill and diligence) with respect to its design. This is less than the higher obligation of expediency which, on the other hand, may be implied under law and customary law. The unchanged DB 2011 does not present the risk of redesigning as part of the employer`s requirements to the contractor.