Quantitative Measures:
These are the aspects of a text such as sentence length, word length, word frequency, and repetition that are best measured by computer software. Learning A-Z utilizes the Lexile Framework for Reading*, developed by MetaMetrics, Inc., for quantitative measurement of texts in English and Spanish.
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Qualitative Measures:
These are text attributes that are best evaluated by a human reader, including factors such as the author's purpose, the levels of meaning, structure of the text, language conventions, language clarity, knowledge demands, and the complexity and importance of visual devices. At Learning A-Z, multiple trained subject matter experts apply their professional judgment to evaluate the complexity of each text, which is represented as a Learning A-Z Level, aa–Z2.
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Reader and Task Considerations:
Each reader brings unique skills, background, and motivation to the act of reading. Teachers should evaluate reader and task considerations, which depend on the circumstances of each student and their interaction with a specific book. Using the combination of Lexile Measures and qualitative measures, teachers can make informed decisions about appropriate texts for the reader and task.