The influence of socioeconomic factors on academic performance leads, as shown by the EVES study, to systematic disadvantages for students from educationally disadvantaged backgrounds as early as elementary school. Furthermore, the stability of the differences in proficiency levels in literacy acquisition among the various elementary school classes is striking. Even though these classes are similar in their sociographic, socioeconomic, and individual characteristics of the children, significant differences in reading and writing skills already exist by the end of the first grade. This considerable variation is primarily attributed to teaching characteristics.