The validation study was conducted to statistically test the validity of the developed DBS. Accordingly, the materials that had been developed for the DBS over the course of the project and had already been tested were used. The parents of all participating children gave their consent. The research ethical standards were adhered to. Likewise, a positive vote of the ethics committee of the University of Leipzig was available. At the same time, further domain-specific test procedures were used to determine convergent and discriminant validity in the areas of early literacy and early mathematics (e.g. MBK 0, Krajewski, 2018; GISC-EL, Koch, Euker & Kuhl, 2016). In addition, a comprehensive rating-based evaluation form was developed for the Early Mathematics Observation Form, with a focus on suitability for everyday use and acceptance in practice. The observation procedures for well-being and the children's questionnaire on well-being were used by project staff, students, and preschool teachers. Convergent discrimination for the habitual well-being rating procedure was determined using a selection of parallel assessment methods (excerpts from KOMPIK; Mayr, Bauer, Krause, Kruse, & Schnirch, 2014; Leiden Inventory for the Child's Wellbeing in Day Care/LICW-D; De Schipper, Van IJzendoorn, & Tavecchio, 2004).