A design metric is a measure of a implementations features such as cost, size, performance and power.
Commonly used design metrics are:
1.NRE cost:
NRE stands for non recurring engineering cost. The one time monetary cost of Designing the system once the system is designed, any number of units can be manufactured without incurring any additional design cost . Hence the term non recurring.
2.Unit cost:
The monetary cost of manufacturing is copy of the system, excluding NRE cost.
3.Size:
The physical space required by the system. It is often measured in bytes for software and Gates or transistor for Hardware.
4.Performance:
The performance is the execution time of the system.
5.Power:
The amount of power consumed by the system, which may determine the lifetime of a battery or quilling requirements of the IC, since more power means more heat.
6.Flexibility:
The ability to change the functionality of the system without incurring heavy NRE cost.
7. Time to prototype:
The time needed to build a working version of the system, which may be bigger or more expensive than the final system implementation but it can be used to verify the system usefulness and correctness and to refine the systems functionality.
8.Time to market:
The time required to develop a system to the point that it can be release and sold to customers. The main contributors are designed time, manufacturing time, and testing time.
9.Maintainability:
The ability to modify the system after its initial release, especially by designers who did not originally designed the system.
10.Correctness:
It's our confidence that we have implemented the systems functionality correctly. We can check the functionality throughout the process of Designing the system, and we can insert test circuitry to check that manufacturing was correct.
11.Safety:
The probability that the system will not cause harm.