One-of-a-Kind Estimates.

Estimated parameters can be for one-of-a-kind or first-runprojects.The first time something is done, it is difficult to estimate costs required to design, produce, and maintain a product over its life cycle. Conside~the. prqjec.tedcost estimates that were developed for the first NASA missions. The U.S. space program initially had no experience with human flight in outer space; thus the development of the cost estimates for design, production, launch, and recovery of the astronauts, flight hardware, and payloads was a "first-time experience."The same is true for any endeavor lacking local or global historical cost data. New products or processes that are unique and fundamentally differentmake estimating costs difficult.

The good news is that there are very few one-of-a-kind estimates to be made in engineering design and analysis. Nearly all new technologies, products, and processes have "close cousins" that have led to their development.The concept of estimation by analogy allows one to use knowledge about well-understood activities to anticipate costs for new activities. Inthe 1950s, at the start of themilitarymissile program, aircraft companies drew on their in-depth knowledge of designing and producing aircraft when they bid on missile contracts. As another example, consider the problem of estimating the production labor requirements for a brand new product, X. A company may use its labor knowledge about Product Y, a similar type product, to build up the estimate for X. Thus, although "first-run" estimates are difficult to make, estimation by analogy can be an effective tool.