and detail between the concept design stage and the detail design stage. Their significance lies in their ability to provide ship cost estimators with reliable results without the time and cost that would be incurred through the use of a detailed engineering analysis of a design. There are five main types of CER's:
" Manual - determined from external information such as vendors and subcontractors
" Calculated - determined and derived from actual previous ship cost data.
" Predictive - determined though regression from return data of multiple vessels over time, or from a common manufacturing method that is changing over time.
" Empirical - determined through statistical regression analysis of particular shipyard processes.
" Standard Interim Products - determined at each level of the PWBS. Existing CER's are grouped together into standard common interim products and modules called re-use packages.