Zone of Proximal Development
The Zone of Proximal Development (ZPD) is a term borrowed from psychologist Lev Vygotsky. In Accelerated Reader, the ZPD is a range of ATOS book levels that are not too challenging and not too easy, depending upon a student's reading level. Although ZPD itself is not entered or calculated in Accelerated Reader, it is a key component of successful reading practice and target setting. STAR Reading provides a ZPD for each student who has tested. The ZPD is approximate. Success at any reading level also depends on the student's interest and prior knowledge of a book's content. Teachers should use their professional judgment to adjust the level of books read to match an individual student's needs and interests.