How accurate is your readability checker?

In today’s digital world, it is easy to use one of the many readability checker programs available to check and hopefully improve your text. But our research project, conducted in partnership with Macquarie University, found that the results of these programs were very inconsistent.

Most readability checkers are built around common readability tools, such as the Flesch–Kincaid tool built into Microsoft Word and other checkers, or the SMOG tool (simple measure of gobbledegook). Readability checkers usually provide a rating in terms of the school grade required to read the text – the Australian Digital Transformation Agency recommends that information for the general public should be tailored to grade 7 or below.

The research found that different readability checkers deliver different results for the same text. SMOG consistently rated texts as far more difficult to read than Flesch–Kincaid. Even more interestingly, different brands using the same tool also delivered different results. For example, different brands using the Flesch–Kincaid tool rated texts up to 2 grades different, and different brands using the SMOG tool rated texts up to 4 grades different.

This result highlights the need for benchmarking. You may need to test your content with members of your audience and align their needs to your checker ratings.

It also highlights that it is important to choose the tool most suited to your content. For example, SMOG is set for 100% comprehension of the text and puts the bar higher than Flesch–Kincaid, which works with 75% comprehension. This may be why SMOG consistently rates texts as harder to read. But this may be important in some contexts – for example, 100% comprehension would be necessary for health professionals.

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