In the study of software project estimation, the Software Equation is a model with multiple variables based on assumptions of a specific distribution of effort throughout the entire length of a software development project. The models basis was formed through analysis of productivity data collected from over 4000 modern day software development projects. The software equation was derived from the Putnam-Norden-Rayleigh Curve which can be used to show the non-linear correlation between time to complete the project and applied human effort.
Contents
Model Form
The estimation model can be described in the following form.
where
Defining B
B, the special skills factor, is related to the size of the product.
Defining P
Research from the collected productivity data supplies initial values for variable P determined by the type of software being developed. Some examples are listed below. These numbers do not apply in all situations and P can often be calculated from previous metrics information.