The analysis deals with the power shifts (caused by the introduction of data-collecting and processing techniques) that can be observed in various relationships: between data-specialists and other civil servants; between different departments within the same Ministry; between different Ministries; between centra! and local administrations; between legislative and executive bodies; between politicians and civil servants. The theoretical bases for the analysis are drawn from the sociology of organizations. The observation itself draws upon the Belgian administration. It leads to more general questions of political science concerning the evolution of some power relationships. What do slogans like «data power» or «computer revolution» mean in real life? The facts are sometimes surprising, and practice at a great distance from theory.