4. Build the cost model using linear regressions

There are two approaches to parametric methods.

• The statistical approach: based exclusively on information from the organization's previous projects, this method proposes a cost estimate based on the organization's own database. The parameters can be freely chosen, and a cost model can be established which is enriched at each end of the project. However, this approach is dependent on the company's ability to build and maintain an exclusive cost database.

• The conceptual approach: based on general costing laws, this method proposes complex mathematical models that enable estimates to be made according to simple, but fixed parameters (mass, volume...). Numerous parametric models exist, providing linear (I = aX + bY + cZ), parabolic (I = aX ⁿ + bY ^...