Pragmatic Approaches to Project Estimation
I have successfully used these estimation techniques: historical data, Delphi, wideband Delphi, relative ranking and sizing, and spikes to gather some data before estimating. I have not successfully used any counting or computing techniques. See McConnell (Software Estimation: Demystifying the Black Art [McC06]) for more information about counting and computing techniques.
Historical Comparison for Estimates
If you’re managing a follow-on release similar to the previous one, you might be able to estimate the duration of the project. “Well, the last time, it took us eight people for six months. This looks about the same size, so my first estimate is the same.” Just remember that projects are not linear. ...