4.8: Readability Testing
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Why Is Readability Testing Important?
Web content authors should use the simplest language possible for the following reasons:
- Plain language will translate more easily for those who may wish to read the site in a different language.
- Plain language will be more accessible to those with lower levels of literacy.
- For a general audience, most readers will appreciate simpler language over the unnecessary use of complex words.
Though appropriate reading level is identified as a Level AAA requirement in WCAG 2.0, this is one Level AAA guideline that most public sites should aim to meet in order to reach the broadest possible audience.
The WCAG 2.0 guideline that is relevant to readability is 3.1.5:
3.1.5 Reading Level: When text requires reading ability more advanced than the lower secondary education level after removal of proper names and titles, supplemental content, or a version that does not require reading ability more advanced than the lower secondary education level, is available. (Level AAA)
Reading Level Test Tools
Automated accessibility checkers like AChecker and WAVE do not test for readability.
You can find a variety of readability test tools by searching the Web for “readability test.” These tools run a variety of algorithms that measure things like word length, number of syllables per word, and sentence length, to come up with a readability score. We have selected one example here for you to include in your Toolkit: The Readability Test Tool.
This tool, like most others, will allow you to enter a URL to a webpage, or paste text into a text area. The output from the test appears in the figure below. In this case the reading level is about grade 10, in the range acceptable to pass Guideline 3.1.5. The first area lists a series of readability indices, calculated using various combinations of the characteristics of the text on the page. If you visit the tool’s site, the measures for these indices are listed. Below the indices is a list of the characteristics of the text content. All of these elements are averaged to come up with an average grade level score.
Figure: Readability Test Results from the Readability Test Tool