Readability

Readability refers to the ease with which a written text is understood by a reader, usually reported as an index such as grade level. A text with a readability of 2.0 (second-grade level) is thought to be easier to read than a text with a readability of 8.5 (corresponding to eighth grade midway through the year).

Studies of text difficulty as judged by the number of uncommon words in a text were undertaken as long ago as the 1920s. In the decades that followed, educators and psychologists developed a variety of reading formulas meant to either guide writers and editors in composing a text to fit the needs of an intended audience or organize groups of texts (text leveling) as part of an instructional scheme aimed ...