Measuring Text Readability Using Reading Level

Measuring Text Readability Using Reading Level

James C. Brewer (Texas Tech University, USA)
DOI: 10.4018/978-1-5225-2255-3.ch129
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Reading Grade Level calculations have been in use for over a century in the United States and have guided the selection of texts used in school programs. Government agencies at all levels, the military in its various branches, and editors of publications have found such formulas of use in setting policy or determining who can participate in programs. As readership is now a worldwide phenomenon with English as the primary language of the Internet, Reading Grade Level calculations can also be useful in creating Web pages and assigning reading texts to large multi-user classes (MOOCs) run over the Internet. In this regard, it is possible for faculty to be assured that the material is reachable to a wide audience by checking Reading Grade Level and providing additional guidance for the more difficult items in the form of discussion or focused questions. Authors can use the formulas as a tool to check the quality of their own writing and improve sections which are unnecessarily complex.
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In mid-nineteenth century America schoolrooms were generally not divided into grade levels. Over time grade levels were added and methods were developed to measure the grade level of texts. As the need for graded material grew, there was an extensive push for more scientific methods to measure the grade level of specific texts used in the classroom. The result was the first readability formulas coming in to use in the 1920s. (Wolf, 2013) Much of the early work on the Flesch-Kincaid Grade Level formula was done by Rudolf Flesch in the 1940s (Flesch, 1979). Flesch had been conducting reading studies, observing readers and how they approach long words, and examining punctuation and sentence length. He was an active proponent of “plain English” and was known though many books, in particular Why Johnny Can't Read: And What You Can Do About It (1955). He was a critic of the “look-say” method of teaching reading popular in the 1950s, and he advocated a method for teaching reading that became known as the “look and guess” method and started a revival of phonics which taught learners to sound out words using rules (Blumenfeld, 2015). The Flesch-Kincaid Readability Test and Reading Ease Test came about from the initial work of Rudolf Flesch and subsequent refinements by J. Peter Kincaid. These changes were added by Kincaid while performing work for the United States Navy. Noting that the Flesch-Kincaid grade level was developed for adults, J. Peter Kincaid pointed out:

Among other things we can reasonably measure: the number of commonly understood words, sentence complexity, the number of abstract ideas, and the use of personal pronouns. Beyond these factors, it takes the expertise of the writer and editor to judge organization of the text and whether or not the text conveys the proper information. (McClure, 1987)

In a 1987 interview J. Peter Kincaid stated:

Key Terms in this Chapter

Automated Readability Index: The index is an alternative to the Flesch-Kincaid Grade Level Formula, and is used for English language materials. The index attempts to supply a grade level number relating to the Unites States usage of grade levels. This index makes use characters per word instead of syllables in the word.

Gunning Fog Index: Robert Gunning developed the Gunning fog index in the 1950s to measure the number of years of school that would be required to read a given text. For example, a fog index value of 17 would require a college graduate.

Flesch Reading Ease Formula: The Reading Ease Formula was developed by Rudolf Flesch to provide a number between zero and 120 to represent the difficulty of a text. Theoretically, there is no lower bound to the number assigned. Lower numbers represent greater difficulty and higher numbers represent greater ease of readability. For example, Reader’s Digest is around 65 and the Harvard Law Review is around 30.

Linsear Write Calculation: The Linsear Write calculation was developed by the United States Air Force for determining the readability of their technical manuals. It relies on manual calculation and note of words that have three of more syllables.

Coleman-Liau Index: The index is another alternative to the Flesch-Kincaid Grade Level and assigns a grade level number relating the Unites States usage of grade levels. The index is intended to be one that can be applied mechanically from text. It relies on the average number of letters per 100 words and the average number of sentences per 100 words.

SMOG Grade: SMOG stands for the “Simple Measure of Gobbledygook” and attempts to measure the number of years of education needed to understand a text. It was widely adapted in health care.

Flesch Kincaid Grade Level Formula: The Flesch-Kincaid Grade Level Formula was originally developed by Rudolf Flesch and further revised by J. Peter Kincaid while working on evaluating the reading level of technical manuals for the United States Navy.

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