However, research and materials are across all grade levels.
The literature review is a written overview of major writings and other sources on a selected topic.
Sources covered in the review may include scholarly journal articles, books, government reports, Web sites, etc.
It is often difficult to separate those aspects pertaining to the middle grades from studies that include the early elementary grades (K-3) and/or secondary school grades (9-12). In our review of research and practices in the schools, we found considerable overlap among these topics.
When appropriate, we have indicated where issues under one topic are related to the other two.