In this article we carry out a preliminary reconstitution of the genealogy of the political decision to integrate Portugal in PISA (Programme for International Student Assessment), promoted by the Organisation for Economic Co-operation and Development, made in 1999 and implemented in 2000. For this we used a comprehensive analysis of newspaper articles, legal texts and documents on education policy as well as of interviews with relevant political actors. The first results of this analysis suggest that the decision, which was not unanimous among the government members with responsibilities in the education field, was taken by normative emulation, and aimed to consolidate a particular direction of the national education policy.