HS (national evaluation) was designed to enhance pediatric primary care for children from birth to age 3 and their families by incorporating preventive developmental and behavioral services into routine practice. The model strived to enhance the knowledge and confidence of caregivers as a means of promoting children’s well-being. It focused on aspects of the caregiving environment amenable to change. Infancy is a suitable period for intervention because it is a time of rapid child development and high stress for parents, and parents are likely to be open to new ideas. The model was designed to be universal, with services offered to all families in participating practices, in recognition that all parents have concerns and questions about their children’s health, behavior, and development. Operating through pediatric practices allowed the program to periodically reach children and parents during the developmentally critical first few years of children’s lives.