Evaluation as an Instrument for Eliminating Political Significance: the Controversy Surrounding the Evaluation of American Schools Voucher -- The school voucher was invented by Milton Friedman in the 60s, and tested out in several American states. It also became the subject of a considerable amount of literature on the other side of the Atlantic, as well as of an evaluation campaign during the 1990 2000 decade. This evaluation resulted in numerous controversies: the main ones will be addressed in this article. The most significant effect of this American evaluation fever when it came to the voucher, was that it managed to depoliticise it. This turned the voucher into a purely technical tool which would be more easily exported abroad; finally reaching French local authorities in its theoretically depoliticised form.