What aspect do readability scales, like SMOG and Raygor, measure?

Readability scales such as SMOG (Simple Measure of Gobbledygook) and Raygor are designed to assess the complexity of written texts. They analyze factors like sentence length and the number of syllables or difficult words to determine how accessible a text is for a specific audience. The primary purpose of these scales is to gauge whether a reader will be able to comprehend a piece of writing based on its readability level.

By indicating the text's comprehensibility, these scales help educators and writers to tailor materials to the appropriate age or grade level, ensuring that the content aligns with the reading skills of the intended audience. Hence, the measurement of text comprehension and complexity levels is the key aspect that these readability scales focus on, making this choice the most accurate.