Good texts are not only characterized by the fact that they contain valuable information. In order to really reach the user, readability plays an important role. The SEO –nerd and his team of the Berlin SEO agency observe time after time that Google evidently uses the flesch kincaid readability as ranking factor.
The score measures the readability of texts. The higher the score on the scale, the easier the texts can be read. Demonstrably, pages that are easily or moderately readable rank higher than difficult ones.
Readability is captured in a value in the flesch kincaid readability aka flesch reading ease that states how much effort the text makes to its readers. Two criteria are crucial for this:
- The average sentence length (ASL)
- The average number of syllables per word (ASW)
Using a formula (FRE German = 180 ASL – (58.5 x ASW)), corresponding values are weighted to give a total score. This score can be compared with the average values of other texts. So the Flesch reading ease states how easy a text is to read compared to other texts.
The index was named after Rudolf Flesch, an author who immigrated to the USA from Austria in 1938. The lowered word “German” in the formula means that it is adjusted for the German language. It is known that German sentences are longer than English ones. By now, many Flesch indices for various languages exist.
A simple example
Fairy tales target readers of all age groups and education levels. Accordingly, they should be easy to read. A typical beginning of a fairy tale could be:
Maria and Paul make a vow to each other.”
A contractual text has to be immaculate. Factors like sentence length and length of syllables are not of importance:
Maria, herewith named the wife, and Paul, herewith named the husband, express their will with their signature on this paper, to bind themselves with the husband or wife to a certified communion of good, commonly known as marriage, hereby, on (insert date here) at the registry.”
The fairy tale sentence has a Flesch index of 89 considered to be extremely easy to read, almost mundane. The legal English has an index of 38 and is classed as very difficult and demanding (if there were more sentence the score would even go down further).
The Flesch reading ease chart
The Flesch reading ease score and what it means for SEO and readers:
90 to 100 = Very easy to read. Easily understood by an average 11-year-old student. (5th grade)
80 to 90 = Easy to read. Conversational English for consumers. (6th grade)
70 to 80 = Fairly easy to read. (7th grade)
60 to 70 = Plain English. Easily understood by 13- to 15-year-old students. (8th & 9th grade)
50 to 60 = Fairly difficult to read. (10th & 12th grade)
30 to 50 = Difficult to read. (college)
0 to 30 = Very difficult to read. Very Confusing. Best understood by university graduates. (college graduate)
Measuring the Flesch index online
On the net there are some tools available you can easily measure the Flesch index by copy-and-paste the Text, or a URL.
If you are looking for a quick reference to the Flesch Index, this page is the right place for you. Just enter a text ore URL and the tool shows you the Flesch Index and highlights difficult words and sentences.
This tool is made for everyone who writes articles. Apart from stating the Flesch index it gives hints on informative content and objectivity of the text. Whether you’re a developer, copywriter, marketer, usability assessor or SEO expert, chances are you already have plenty on your mind
This tool is open for various text kinds. Besides the Flesch index an the tool also displays complicated sentences (with many words and syllables) with suggestions for what you might do to improve its readability. It also counts:
- Number of characters (without spaces)
- Number of words
- Number of sentences
- Average number of characters per word
- Average number of syllables per word
- Average number of words per sentence
- und mehr …
The recommendations of these tools should not be followed too precisely either, though. For instance, all filler words are marked on. But not always you can just dismiss them. Example: when categorizing the Flesch Index “very easily readable” “very” is marked as a filler word. If you were to discard it the difference to “easily readable” would be missing.
The Flesch index serves Search Engine Optimization (SEO)
Officially the Flesch index has not been confirmed as a ranking factor by Google yet. If the score is considered in SEO analyses, though, there is a regular trend that sites with scores between 30 and 70 rank better. Since Google has been working for years to lead its algorithm to an understanding of contents close to users (more on this on SXO) the application of a comprehensibility index fits right into the picture.
At first glance, measuring readability using two criteria looks like bean counting but both factors are the basic requirement for understanding texts. Texts become comprehensible, according to the Hamburger model, by:
- Simplicity – short sentences (9 to 13 words), short words (on average no more than 3 syllables), no use of specific terminology
- Syntax – per sentence only one thought should be expressed. The elementary part of the text is at the beginning of the sentence. Paragraphs signal related thoughts.
- Conciseness – a metaphorical language, many verbs
- Stimulation – the text is complemented with pictures and graphs
OnPage SEO that aims to be sustainable has to benchmark itself to these criteria. In the sense of a holistic SEO that considers itself as an optimization of search experience the Flesch index is one point of orientation helping designing sites more attractive for users.