Evaluate XP effectiveness using simulation modeling

Effectively evaluating the capability of a software development methodology has always been very difficult, owing to the number and variability of factors to control. Evaluating XP is by no way different under this respect. In this paper we present a simulation approach to evaluate the applicability and effectiveness of XP process, and the effects of some of its individual practices. Such approaches using simulation are increasing popular because they are inexpensive and flexible. Of course, they need to be calibrated with real data and complemented with empirical research. The XP process has been modelled and a simulation executive has been written, enabling to simulate XP software development activities. The model follows an object-oriented approach, and has been implemented in Smalltalk language, following XP process itself. It is able to vary the usage level of some XP practices and to simulate how all the project entities evolve consequently.