YS_CITO

The CITO-test is a standardized test for educational achievement that is administered in the final grade (when children are 11 or 12 years old) of elementary school (Eindtoets Basisonderwijs 2002, Arnhem: Citogroep, 2002). It consists of multiple choice items in 4 different educational skills, namely Arithmetic, Language, Study Skills, and Science and Social Studies. All scores on the scales are standardized to percentile scores to correct for differences in the number of items across the years. The first 3 test scales are combined to a standardized Total score (also called CITO final test score), which is standardized on scale from 500 to 550. The information on CITO-score is obtained at different ways: 1) surveys teachers of twins (CITO final test scores and sub scores); 2) survey parents of twins (CITO final test scores and sub scores); 3) survey to twins (CITO final test scores); and 4) for a small number of twins, the CITO-scores are obtained by linking our data to the national base of CITO, by using the LVS data, and by project (YS_DT).