Formerly, No Child Left Behind legislation describes arts education as "essential to every child's education," and include it as one of the Core Subjects. No Child Left Behind legislation also emphasizes accountability through assessment (often taking the form of the standardized test.) While no standardized assessment has been mandated in any of the arts, the need for academic accountability in the arts, as well as in other academic subject areas, has led to increased research on and advocacy of arts integration and its impact on student learning.