As of now I have done effort estimation based on experience and recently using function points.
I am now exploring UCP, read this article http://www.codeproject.com/KB/architecture/usecasep.aspx. I then checked various other articles based on Use Case Points (UCP). I am not able to find out how exactly it works and is it correct.
For example, I have a login functionality where user provides userid and password and I check against a table in database to allow or deny login. I define a user actor and Login as a Use Case.
As per UCP I categorize Login use case as Simple and the GUI interface as Complex. As per UCP factor table I get 5 and 3 so the total is 15. After applying the technical factor and environmental factor adjustment it becomes 7. If I take productivity factor as 20 then I am getting 140 hours. But I know it will take at most 30 hrs along with documentation and testing efforts.
Am I doing something wrong in defining the Use Case here? UCP says if the interface is GUI then its complex but here the gui is easy enough so should I downgrade that factor? Also factor for simple is 5, should I define another level as Very Simple? But then am I not complicating the matter here?
Part of the issue may be how you’re counting transactions. According to the author of UCP, transactions are a “round trip” from the user to the system back to the user; a transaction is finished when the system awaits a new input stimulus. In this case, unless the system is responding…a logon is probably just 1 transaction unless there are several round trips to and from the system.
Check out this link for more info…
http://www.ibm.com/developerworks/rational/library/edge/09/mar09/collaris_dekker/index.html