The dataset contains all raw data used for analyses in the research of Braams and Bosman (2000), and Study 3 described by Walda, et al. (in preparation). The manuscript of Braams and Bosman addressed kindergarten predictors of reading and spelling level. The manuscript of Walda et al. (in preparation) addressed the identification of determinants of dyslexia by traditional, linear techniques as well as machine learning techniques. For a full description of all measures see the README file. The experiment design was a longitudinal repeated measures design. During three moments of measurement tests were administered in an one-to-one assessment setting. The dataset includes test scores for phonological awareness and initial word decoding. Phonological awareness was assessed once: In the last year of Kindergarten (T1). Word decoding was assessed twice: Halfway Grade 1 (T2), and at the end of Grade 1(T3).