Abstract
A limited budget for IT may lock public bodies in obsolete inefficient solutions slowing down their process of innovation. Various actions of estimating, controlling, and reducing IT costs have been already performed at national and European levels and Open Source Software (OSS) has been often pointed as a promising alternative that may also render public services and the underlying business processes more transparent and accessible to citizens. In this chapter, we propose a model of cost of a migration to OSS as a decision making instrument that helps public bodies being autonomous and independent in the IT adoption. The model is empirically validated in the real daily operations of more than 3,500 users. If adopted systematically our model might be a powerful tool to support transformational government and to establish an empirical open knowledge base on the economic advantages of OSS on which to found future strategies of OSS adoption.