ABSTRACT
This chapter considers the thorny topic of the cost impact of collaborative working from a number of perspectives, splits the problem into two main elements: the development cycle and the production cycle, as there are different drivers involved. It also considers two alternative models for assessing the impact across a number of equal partners: the Square Root Rule, and the Reciprocal or Parabolic Rule, both of which use the number of partners to calculate the development penalty factor. The chapter argues that a more general form of the square root rule was a standard power function model with an exponent between 0 and 1. It explores the strengths and weaknesses of the two models, but as these are virtually impossible to calibrate, estimators cannot say which is necessarily the better. The chapter concludes that, whilst collaborative working did distribute the work and spread the cost and risk over a number of partners.
