ATOS for Text - ATOS Text Complexity Analyzer

Determining Text Complexity level is now easier than ever.

The ATOS readability formula is a research-proven tool to guide students to appropriate-level books. Confirmed as a valid and reliable text complexity measure for the Common Core Standards, ATOS takes into account the most important predictors of text complexity—average sentence length, average word length, and word difficulty level. The results are provided in a grade-level scale that is easy to use and understand.

CCSS Study

Confirmed as a valid and reliable text complexity measure for the Common Core standards.

ATOS is the first formula to include statistics from actual student book reading, not just data based on short text passages. ATOS supports the quantitative dimension of the CCSS definition of text complexity.

Adapted from Appendix A of the CCSS for English Language Arts and Literacy.

Qualitative factors include levels of meaning, structure, language conventionality, clarity, and knowledge demands. Interest level (i.e., content and maturity level of text) and genre are provided in AR BookFinder.

Quantitative dimensions include word length or frequency and sentence length that can only be measured efficiently by computer software.

Reader and Task considerations include students’ motivation, knowledge, and background interests along with the purpose and complexity of task assigned, and are best made by the teacher.

Guide students to books at the appropriate level.

STAR Reading determines students’ reading level range or Zone of Proximal Development (ZPD) and automatically imports results into AR. Students are encouraged to read mostly within their ZPD to optimize growth and success. AR provides ATOS readability and interest level information on over 160,000 book titles.

Try the free ATOS Analyzer.

To find the ATOS readability level for any text, our free ATOS Online Analyzer will provide quick, accurate and easy to understand results—including recommended ATOS level ranges for CCSS Grade Band correlations.

ATOS Analyzer