Why is readability important for SEO?
It is unclear whether readability is used as a organic ranking factor explicitly. We thus do not know whether or not Google uses something like the Flesch score (or a variation for that matter) as a ranking factor in its algorithm.
If the difficulty level of your text is too high, the text is too hard to read for your audience. Your audience then will not stay on your website and search for information elsewhere. A difficult text will result in a high bounce rate and this will lead to lower ranking in the long run. So, you should definitely make sure your texts are well written and not too difficult.
How is the Flesch reading ease score calculated?
Flesch reading ease measures textual difficulty of a reading passage in English (note: in languages other than English, Flesch is seriously unreliable).
The lower the score, the more difficult the text is. The Flesch readability score uses the sentence length (number of words per sentence) and the number of syllables per word in an equation to calculate the reading ease. Texts with a very high Flesch reading Ease score (about 100) are very easy to read, have short sentences and no words of more than two syllables. Usually, a reading ease of 60-70 is believed to be acceptable/ normal for web texts.
Post Source: Yoast SEO Blog
Post Orignal URL: https://yoast.com/flesch-reading-ease-score/