EU planning documents enhance the values of polycentrism, as a tool to promote a more efficient, equitable and sustainable development. This paper highlights how and suggests why a descriptive approach of the European urban system became progressively a normative concept. It examines how biases in the measurement of polycentricity in the ESPON 1.1.1 report are related to this normative approach. Our empirical findings doesn't suggest any clear correlation between more polycentricity and more economic efficiency or even more spatial equity. The paper examines the reasons of the EU tenacity to promote polycentrism. This concept seems to be the result of a political compromise and a strange hybrid between two competing approaches for the future of the European space.