ICCS 2009 Technical Report - IEA

B.12. Estonia• Schools for adults, special education schools, very small schools (fewer than five studentsin the target grade), international schools where English is the language of instruction, andWaldorf schools were excluded at the school level.• Explicit stratification was performed by language (Estonian, Russian, Estonian, andRussian), resulting in three explicit strata.• Implicit stratification was applied by urbanization (urban, rural), giving a total of siximplicit strata.Table B.12.1: Allocation of student sample in EstoniaSchool Participation Status—Student SurveyParticipating SchoolsExplicit Strata Total IneligibleNon-ParticipatingSampled Schools Schools Sampled First Second Schoolsreplacement replacementEstonian 116 6 107 2 0 1Russian 30 3 26 0 1 0Estonian and Russian* 4 0 3 1 0 0Total 150 9 136 3 1 1Notes:One school was regarded as non-participating because the within-school participation rate was below 50%.*All students in the four selected schools from this stratum were tested in the Estonian language.Table B.12.2: Allocation of teacher sample in EstoniaSchool Participation Status—Teacher SurveyExplicit StrataParticipating SchoolsTotal IneligibleNon-ParticipatingSampled Schools Schools Sampled First Second Schoolsreplacement replacementEstonian 116 6 103 2 0 5Russian 30 3 23 0 1 3Estonian and Russian 4 0 3 1 0 0Total 150 9 129 3 1 8Note: Two schools were regarded as non-participating because the within-school participation rate was below 50%.B.13. Finland• Schools on Åland and special education schools were excluded at the school level.• Explicit stratification was performed by region (five levels) and urbanization (rural, semiurban,or rural), resulting in 10 explicit strata.• No implicit stratification was applied.294 ICCS 2009 technical report