Other formulas do a poor job of measuring the readability of emergent-reader books, and often understate them. ATOS specifically addresses the challenges of leveling these books. Researchers utilized the Reading Recovery scale to identify key variables for leveling such books. Other formulas did not adjust for the greater difficulty of nonfiction. ATOS, by taking length and graded vocabulary into account, more accurately levels nonfiction books.
Readability is a very important tool that teachers can use to accelerate learning.
We wanted to improve reliability and accuracy of readability estimates. We wanted to develop a formula specifically designed for matching students and books. Teachers needed a formula to deal with evaluating fiction vs. nonfiction. That s the actual literature reading and testing done by over 30,000 students. This is the first time that substantial data on actual student book reading has been incorporated into a readability formula.