The method for determining the size estimate to develop a system is based on a calculation with the following elements:
Unadjusted Use Case Weight (UUCW) – the point size of the software that accounts for the number and complexity of use cases.
Unadjusted Actor Weight (UAW) – the point size of the software that accounts for the number and complexity of actors.
Technical Complexity Factor (TCF) – factor that is used to adjust the size based on technical considerations.
Environmental Complexity Factor (ECF) – factor that is used to adjust the size based on environmental considerations.
https://en.wikipedia.org/wiki/Use_Case_Points