From birth on, child outcomes are influenced by both child characteristics and preconditions on the one hand and by characteristics of different learning environments on the other. Despite many studies on early child development, relatively little is known about the interaction of child characteristics and learning environments (and the mutual interaction of learning environments with each other) in this age. Specifically, representative longitudinal large-scale studies that investigate this field of research are sparse, partially outdated, and still missing completely in Germany. As maternal leave and day-care regulations as well as culturally contingent attitudes influence home and external day-care learning environments and differ widely between countries, general conclusions as well as conclusions for the German context in particular have to be drawn with caution from these studies (International Labour Office, 2013; Waldfogel, 2001). The birth cohort study of the National Educational Panel Study (NEPS) aims to close this gap and will provide longitudinal information based on different measurement points (Wave 1 with children at the age of 7 months, Wave 2 at the age of 15 months, Wave 3 at the age of 26 months, and Wave 4 at the age of 37 months). Information is not only gleaned from parents reports but also from video data of test situations and parent-child interaction in a household setting (n = 3,481). Children are tested using (a) a habituation/dishabituation paradigm assessing early attentional and learning abilities as well as (b) items adapted from a revised version of the Bayley Scales of infant development (Bayley, 2006). In addition, information about the child and the home learning environment (HLE) is given by video-taped parent-child interactions. The ViVA project was established to validate NEPS data and to enrich the Scientific Use File (SUF) of the NEPS with a special focus on domain-specific competencies and interaction behaviour. Aims of the ViVA I and II project cover: (1) validation of NEPS data, (2) adding further indicators of child characteristics and learning environments to the NEPS SUF, and (3) providing substantive analysis of (domain-specific) competence development in relation to the home and the day-care learning environment. While ViVA I focuses on validation and analysis of Waves 1 and 2 of the NEPS data, ViVA II should focus on wave 3, on the home and the external day-care learning environment, and on longitudinal analyses.