Key System Characteristics and Performance Parameters
Each system has unique physical and performance characteristics; analysts need specific knowledge about these characteristics before they can develop a cost estimate for a weapon system, an information system, or a construction program.
While the specific physical and performance characteristics for a system will vary from one program to another, several general characteristics have been identified in the various guides we reviewed. Table 5 lists general characteristics shared within several system types. Table 5 is not intended to be exhaustive.
Table 5: General System Characteristics
| System | Characteristic |
|---|---|
| Aircraft | Breakdown of airframe unit weight by material type |
| Combat ceiling and speed | |
| Internal fuel capacity | |
| Length | |
| Load factor | |
| Maximum altitude | |
| Maximum speed (knots at sea level) | |
| Mission and profile | |
| Weight (for example, airframe unit weight, combat, empty, maximum gross, payload, structure) | |
| Wetted area | |
| Wing (for example, wingspan, wing area, wing loading) | |
| Automated information systems | Architecture |
| Commercial off-the-shelf (COTS) software used | |
| Customization of COTS software | |
| Expansion factors | |
| Memory size | |
| Processor type | |
| Proficiency of programmers | |
| Programming language used | |
| Software sizing metric | |
| Construction | Ability to secure long-term visas |
| Changeover | |
| Environmental impact | |
| Geography | |
| Geology | |
| Liability | |
| Location (for example, land value, proximity to major roads, relocation expenses for workers) | |
| Material type (for example, composite, masonry, metal, tile, wood shake) | |
| Number of stories | |
| Permits | |
| Public acceptance | |
| Square feet | |
| Systemization | |
| Missiles | Height |
| Length | |
| Payload | |
| Propulsion type | |
| Range | |
| Sensors | |
| Weight | |
| Width | |
| Ships | Acoustic signature |
| Full displacement | |
| Full load weight | |
| Length overall | |
| Lift capacity | |
| Light ship weight | |
| Margin | |
| Maximum beam | |
| Number of screws | |
| Payload | |
| Propulsion type | |
| Shaft horsepower | |
| Space | Attitude |
| Design life and reliability | |
| Launch vehicle | |
| Mission and duration | |
| Orbit type | |
| Pointing accuracy | |
| Satellite type | |
| Thrust | |
| Weight and volume | |
| Tanks and trucks | Engine |
| Height | |
| Horsepower | |
| Length | |
| Weight | |
| Width | |
| Payload |
Source: DOD and GAO | GAO-20-195G
Once a system’s unique requirements have been defined, they should be managed and tracked continually throughout the program’s development. If requirements change, both the technical baseline and cost estimate should be updated so that users and management can understand the effects of the change. Because it is evolutionary, earlier versions of the technical baseline will necessarily include more assumptions and, therefore, more uncertainty. These assumptions should be replaced with information as they become known; consequently, the level of uncertainty associated with the assumptions will decline.