Flesch-Kincaid Readability Test

The Flesch/Flesch–Kincaid Readability Tests are readability tests designed to indicate comprehension difficulty when reading a passage of contemporary academic English. There are two tests, the Flesch Reading Ease, and the Flesch–Kincaid Grade Level. Although they use the same core measures (word length and sentence length), they have different weighting factors, so the results of the two tests correlate imperfectly: a text with a higher score on the Reading Ease test over another text may have a lower score on the Grade Level test. Both systems were devised by Rudolf Flesch.

Flesch Reading Ease

In the Flesch Reading Ease test, higher scores indicate material that is easier to read; lower numbers mark more-difficult-to-read passages. The formula for the Flesch Reading Ease Score (FRES) test is

:$206.835\; -\; 1.015\; left\; (\; frac\{mbox\{total\; words\{mbox\{total\; sentences\; ight\; )\; -\; 84.6\; left\; (\; frac\{mbox\{total\; syllables\{mbox\{total\; words\; ight\; )$Here's the breakdown,

"Reader's Digest" magazine has a readability index of about 65, "Time" magazine scores about 52, and the "Harvard Law Review" has a general readability score in the low 30s. The highest (easiest) readability score possible is 121 (every sentence consisting of only one-syllable words); theoretically there is no lower bound on the score -- this sentence, for example, taken as a reading passage unto itself, has a readability score of ~21.9. This paragraph has a readability score of ~53.93.

Many government agencies require documents or forms to meet specific readability levels.Fact|date=June 2007 The U.S. Department of Defense uses the Reading Ease test as the standard test of readability for its documents and forms.Fact|date=June 2007

Use of this scale is so ubiquitous that it is bundled with popular word processing programs and services such as KWord, Lotus WordPro, Microsoft Word, and Google Docs.

Long words affect this score significantly more than they do the grade level score.

Flesch–Kincaid Grade Level

An obvious use for readability tests is in the field of education. The "Flesch–Kincaid Grade Level Formula" translates the 0–100 score to a U.S. grade level, making it easier for teachers, parents, librarians, and others to judge the readability level of various books and texts. It can also mean the number of years of education generally required to understand this text, relevant when the formula results in a number greater than 12. The grade level is calculated with the following formula:

:$0.39\; left\; (\; frac\{mbox\{total\; words\{mbox\{total\; sentences\; ight\; )\; +\; 11.8\; left\; (\; frac\{mbox\{total\; syllables\{mbox\{total\; words\; ight\; )\; -\; 15.59$

The result is a number that corresponds with a grade level. For example, a score of 8.2 would indicate that the text is expected to be understandable by an average student in 8th grade (usually aged 13-15 in the U.S.).

The lowest grade level score in theory is -3.4, but, since there are few real passages that have every sentence consisting of a single one-syllable word, this rarely occurs in practice. Green Eggs and Ham by Dr. Seuss comes close, averaging 5.7 words per sentence and 1.02 syllables per word, with a grade level of -1.3. (Most of the 812 words are monosyllabic; "anywhere," which occurs eight times, is the only exception.)

References

* Rudolf Flesch (1948); "A new readability yardstick", Journal of Applied Psychology, Vol. 32, pp. 221-233
* Kincaid, J. P.; Fishburne, R. P., Jr.; Rogers, R. L.; and Chissom, B. S. (1975); "Derivation of new readability formulas (Automated Readability Index, Fog Count and Flesch Reading Ease Formula) for Navy enlisted personnel", Research Branch Report 8-75, Millington, TN: Naval Technical Training, U. S. Naval Air Station, Memphis, TN
* Farr, J. N., Jenkins, J. J., and Paterson, D. G. (1951), "Simplification of Flesch Reading Ease Formula", Journal of Applied Psychology, Volume 35, Number 5, (October), pp. 333-337

External links

* [http://flesh.sourceforge.net Flesh] free-standing, Java-based, multi-platform Flesch-Kincaid Readability and Flesch Reading Ease Level tool.
* [http://www.gnu.org/software/diction/diction.html GNU Style and Diction] Command line programs to calculate score
* [http://plainlanguage.com/newreadability.html PlainLanguage.com] All About Readability
* [http://www.eric.ed.gov/ERICDocs/data/ericdocs2sql/content_storage_01/0000019b/80/1b/bf/46.pdf The Principles of Readability] a brief introduction to readability research

Web services

* [http://writing.teiru.net/fog Online readability tool] based on the Perl [http://kobesearch.cpan.org/htdocs/Lingua-EN-Fathom/README.html Lingua::EN::Fathom module] and [http://writing.teiru.net/fog/style.html the GNU Style program] . Text to be analyzed must be on the web with a URL ending in ".txt". Originally written as a resource for [http://www.nanowrimo.org National Novel Writing Month] participants.
* [http://www.spywareguide.com/analyze/analyzer.php Eula Analyzer] – online end-user license agreement analyzer; tests for readability and highlights areas needing scrutiny.
* [http://www.editcentral.com Readability calculators] – displays six readability statistics.
* [http://labs.translated.net/text-readability/ Readability analyzer] and [http://labs.translated.net/terminology-extraction/ terminology extraction] .
* [http://www.addedbytes.com/tools/readability-score/ Check Text Readability] – PHP-based web form.
* [http://docs.google.com/ Google Docs] has readability test sections in the Tools menu.