Cost analysis in the time domain

Government costs analysts must often construct models using production data that are limited by a contract between the producer and the government. The producer usually does not share cost data with the government unless the contract requires that data are reported. Also, the data that are reported are often not in the proper form for constructing mathematical models; that is, cost data are often provided by production unit or lot, while economic and accounting data are usually reported by time period. This paper provides a mathematical link between unit or lot data and time series data; that is, between the units domain and the time domain. The analysis is relevant for made-to-order production, the case where a relatively smaller number of specialized items are produced to contractual order, as in defense and other government contract situations.