Please help me out regarding this
I have read that during Initiation phase (ie when requirements are not gathered yet and we have only the high level prelimenary scope statement ready) we do estimate using either of following methods to get the ROM (Rough order of magnitude)
1) top down approach (Analogous)
2) top down approach (parametric)
3) WBS (Well we cant do this as we dont have requirements yet)
Now my question
Initiation phase :-
1) Analogous : When we have similar projects done earlier which resemble the one which we are doing now then we can use.
Q) What if we dint do similar project ? Then how can we estimate
2) Parametric : All examples in internet show only estimation per unit. Its makes sense for a construction project. What about software project? How can this be done using concept of price per unit ?
3) I know how to use Use Cases and have read an article about use Case point estimation.
Can this be used in Execution phase of project management ?
4) During project does a project manager have to do various estimations at DIFFERENT stages of SDLC ?
I really am not sure about these points. Could you please let me know in detail.
I have come up with these questions as I havent found any answers after googling though.