The term "active learning" is used in a variety of educational contexts. As described in this guide, however, it refers to an instructional approach developed by Lilli Nielsen--a Danish psychologist--for promoting the learning and development of children who have significant support needs. Nielsen's Active Learning involves a range of strategies, including developmentally appropriate, enriched environments that foster independent learning. It is most effective for children of any age who are functioning at a developmental age of birth to 48 months, although it can be used with children at higher development levels. Practitioners using this approach must have specific training on its underlying theory and methods. This NCDB Practice Guide outlines the essential components of Active Learning strategies.