DOI: 10.60641/y3ez-2a04
title: CITO score

description: The Netherlands Twin Register (NTR) consists of individuals who have agreed to participate in twin-family studies and was established and is managed by the Department of Biological Psychology, VU University Amsterdam (see: https://tweelingenregister.vu.nl/). The NTR was established in 1987 and has enrolled around 120.000 twins and a roughly equal number of their relatives. The majority of twin families have participated one or more times in survey studies on a host of epidemiological variables including social demography, personality, lifestyle, somatic and mental health, and subsamples took part in biomaterial collection (e.g. DNA) and dedicated projects for e.g. neuropsychological, biomarker, and behavioral traits. The recruitment into the NTR is fully inclusive without any restrictions on enrolment. The NTR is committed to actively seek the commitment of its participants to science and their continued involvement in NTR research by maintaining a website, electronic newsletters, and the MijnNTR portal that provides personalized feedback to participants. The NTR resources, e.g. the longitudinal phenotyping, the extended pedigree structures, and the multi-generation genotyping allow for future twin-family research that will contribute to gene discovery, causality modelling, and studies of genetic and cultural inheritance of behavioral traits and mental and physical health. In the CID data catalogue, only the NTR projects for children and adolescents (<18 years of age) have been included. This is refered to as the Young Netherlands Twin Register (YNTR). 
description: 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. The CITO-test 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.
description: In NTR, the information on CITO-score is obtained at different ways. Initially, we obtained the CITO final test scores and sub scores from surveys mailed to teachers of twins. Because results are only available near the very end of the school year and the response was low, we later requested the parents to report the scores on the CITO final test scores and sub scores. 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). In addition to the form with extended information on CITO scores, the CITO final test scores are also asked in a mailed survey to parents of 12 year old twins and in the mailed self report surveys (DHBQ). Combined over the different ways in which the data was collected, information on CITO final test scores is available for about 17000 twins/siblings, and for about 12000 twinsm information on subtests is available.