Hierarchical XP
  XP is a light-weight methodology suited particularly for small-sized teams that develop software which has only vague or rapidly changing requirements. The discipline of systems engineering knows it as approach of incremental system change or also of "muddling through". In this paper, we introduce three well known methods of reorganizing companies, namely, the holistic approach, the incremental approach, and the hierarchical approach. We show similarities between software engineering methods and company reorganizationprocesses. In this context, we discuss the extreme programming (XP) approach and how the elements of the hierarchical approach can improve XP. We provide hints on how to scale up XP to larger projects e.g. those common in the telecommunication industry. 
Carsten Jacobi, Bernhard Rumpe
cs.SE