Reading level

Readability is the ease with which a reader can understand a written text. In natural language, the readability of text depends on its content (the complexity of its vocabulary and syntax) and its presentation (such as typographic aspects like font size, line height, and line length). Researchers have used various factors to measure readability, such as

Readability is more than simply legibility—which is a measure of how easily a reader can distinguish individual letters or characters from each other.

Higher readability eases reading effort and speed for any reader, but it is especially important for those who do not have high reading comprehension. In readers with average or poor reading comprehension, raising the readability level of a text from mediocre to good can make the difference between success and failure of its communication goals.

Readability exists in both natural language and programming languages, albeit in different forms. In programming, things such as programmer comments, choice of loop structure, and choice of names can determine the ease with which humans can read computer program code.

People have defined readability in various ways, e.g., in: The Literacy Dictionary, Jeanne Chall and Edgar Dale, G. Harry McLaughlin, William DuBay.

Easy reading helps learning and enjoyment, so what we write should be easy to understand.

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Wikipedia