National evaluation educational priority policy at elementary schools, survey school heads and teachers.

Number of pupils / number of primary years / number of working-class children / number of bargees' children / number of children from ethnic minority background / number of children from trailer parks / number of staff members / number of immigrant staff members / working experience of staff members / sick leave of staff members / type of extramural assistance for disadvantaged pupils / implementation of educational priority policy / whether school belongs to an educational priority area / parental participation / intercultural education / minority language and culture teaching (OETC - 'Onderwijs in eigen taal en cultuur') / language teaching / link between school and life-situation of pupils / differentiation in teaching language skills and arithmetic / teaching method / contact between teachers and parents / guidance of pupils from ethnic minority background