This paper exposes the first stage of a broader study that intents to improve schooling efficacy by identifying and describing the best practices developped in Spanish schools, and which are oriented to obtain the best levels of achievement with students from diverse cultural backgrounds. These best practices will be collected and disseminated in a repertory, that will be available on paper and on the website. The theoretical background of this research is the School Efficacy Improvement Approach which proposes a revision of two main concepts: “educational achievement” and “best practices”. These revision has been undertaken since a double perspective: firstly, analyzing the most meaningful research contributions in the last ten years; and, secondly, taking into account the opinions of some experts _ teachers, educational counsulting, families, students, technicians, sociocultural agents_ concerned by this subjects.

The presentation will focus on describig the methodological tool designed and implemented to undertake the “expert survey”: the Delphi method. The Delphi process has been iteractive and interactive, in order to gather the participants´opinions several times and give them a chance to review their opinions. Special attention has been paid to guarantee the permanent feedback and the statistical group output. The questionnaire has been the basic instrument to collect information. In the first turn of consultation, we have included open questions in the questionnaire. The answers has been analysed according to the qualitative approach. We have designed a second questionnaire in basis on this information. In this case, the second questionnaire has been a scale and it has provided quantitative information which has allowed know the level of agreement about our topics of study. In this paper, we are going to present the results that we have obtained in this second turn. In this process, it was very important to define some saturation criterions: consensus as convergence of individual estimations, and stability as maintenance of opinions.

It’s very interesting to analyse the different opinions about our two topics of study and to know the differences between specific profiles of experts. This analisys will allow to know the nuances in the opinions about “educational achievement” and “school practice”