Reducing the early school dropout rate is one of the main objectives established by the European Union in regards to Education for 2020. Each and every country of the Union have echoed this objective, together with the reduction of school failure and the improvement in education. Few times, however, these objectives, together with the indicators that periodically appear showing the degree of fulfilment, are contemplated from a gender perspective. Therefore, the differences in academic results by sex, both in Compulsory Education as in Post-Compulsory Education and in Tertiary/Higher Education, are already a phenomenon verified at a worldwide level in the total of the evaluation of education systems, both of a national and international nature.
In this research context the general aim of this thesis has been to study and explain the observable gender patterns in Spanish students and in the achievement of basic competences, from a statistical analysis of the data taken by the Ministry of Education, through the Institute of Evaluation, in the ‘General Evaluation of the Spanish Education System’ (’Evaluación General del Sistema Educativo Español-EGSE), carried out in the year 2007.
In order to achieve the above mentioned general objective, in first place the procedure has been to carefully revise the antecedents of the research  within the international and national context from the study of public policies on Equality  in Europe and in Spain, the main results on education and the different gender patterns detected in the main international evaluations backed by the OECD (PISA, PIRLS, TIMSS) and the Spanish Education results according to gender, exploiting, for that, the statistics on education which are compiled by the Spanish Ministry of Education, Culture and Sport. Likewise, an exhaustive compilation of the scientific production regarding gender and educational achievement, revising the main results of the investigation has been carried out.    
First, a gender-based descriptive statistical analysis  regarding each variable included in the questionnaire of the EGSE students is offered, rendering a matrix of gender patterns (matriz de patrones de género). This matrix clearly shows collective behaviours in the education results, predictable depending on the sex, which in this thesis have been called ‘steady gender pattern towards education performance’ (patrón de género estable ante el rendimiento educativo-PGRE), and which confers an advantage to boys compared to girls in Mathematics and Science and to girls compared to boys in Spanish Language and English Language. Apart from identifying the existence of PGREs, this thesis establishes the existence of situations where this steady pattern is modified in two opposite directions. In the first case there is not the common advantage of boys in Sciences and Mathematics, or the consolidated advantage of girls in Spanish Language and English Language, being this situation called in this thesis ‘altered gender pattern towards the education performance’ (patrón de género alterado ante el rendimiento educativo-PGRA) for the case of an advantage of girls in at least three of in the four competences studied. The second situation is named ‘inverse altered gender pattern’ (patrón de género alterado inverso-PGRAi) and it describes the situation, which is quite exceptional, in which the boys are superior to their classmates in at least three, but usually in the four subjects evaluated. 
The results of the research allow the identification of the most relevant factors related to educational performance in Spanish Language and Mathematics obtained by statistical data reduction techniques, such as factor analysis and multiple correspondence analysis. Some multilevel models have also been obtained, allowing a better estimate of the effects of the different factors on performance. In these models the gender factor stands out, with a very significant effect on performance both in Spanish Language and Mathematics. Nevertheless, the effect of this factor shows a different direction depending on the measured subject. Being a woman has a positive effect on Spanish Language competence, while in Mathematics competence the effect is the opposite.