The product design process can be viewed as a chain in which decisions about the concept are linked to decisions about the detail. This chain can be extended to include the design and operation of the 'downstream' business processes that ultimately manufacture and support the product. From this view of the design process, a set of key requirements for the evaluation of design decision chains has been derived. The idea of decision chains is illustrated using an enterprise simulation that is considered to provide the necessary capabilities to analyse the chain of dependent decisions to the required detail. How such a system could be used in product design is also discussed.