- Estimate the number of screens in the application that need to be developed
- The RoM of the project in person months = Count of Screens to be developed
- E.g. if there are 100 screens to be developed, the RoM of the project is 100 person months.
Note that this is only an RoM method, or estimation with a large degree of tolerance, perhaps 25% or so.
I have used this thumb rule with a large degree of success for dot net based projects. My guess is that it should work pretty much the same with other platforms like Java and even SAP and other ERP systems as well. I do not have any historical data, however, to substantiate this.
Since this is an effort estimation rule and not a sizing rule, the figure will differ from one team to another. You will need historical data to arrive at a figure that better reflects the productivity of your team.
The point is that there is a correlation between the number of screens and the effort. Obviously, it is rather simplistic and hence suitable only for a quick computation of the RoM. For business applications, I have used function point for dog’s years, and trust it very much. That is what I would recommend for a more accurate estimation.