Time Distribution of Software Stage Effort

In the 1950s, Norden first employed the Rayleigh Curve to describe the time distribution rule of software project effort. However, to date, there is no new curve proposed for the later software projects. This research explores a new distribution rule which leads further to estimate software stage effort. We conducted a study on the basis of 4,516 actual projects, and derived general monthly effort distribution curves from them. The new curve has some features similar with Norden's curve, but there also exist some obvious differences. Benefit from a large number of projects, we also found the monthly effort statistical distribution and the typical value of each month. The research results give a new facet about software projects within the dataset, and can be helpful for software project management.