If you need to make sure your writing is clear, the website Readability Score can help.
I’m not connected or affiliated to this website or its creator in any way, I just find it very useful, and wanted to share it with you.
Much of my working life involves writing, so to all intents and purposes I am a professional writer.
I want to show you why I find this site useful, and give you some recommendations on how to use it.
What is a readability score? What is a readability index?
The concept of a readability score (also known as a readability index) goes back many years, really hitting its stride in 1975, when Rudolf Flesch and J. Peter Kincaid built their Flesch–Kincaid readability tests for the US Navy.
The idea is that by looking at your writing, and making some calculations, we can figure out roughly how easy it is for somebody to understand what you’ve written.
It’s an automated calculation, so of course it’s not perfect, but it’s a very useful guide. The most common measures that these scores look at is sentence length, word length, number of syllables in your words, and the number of characters (letters) that you use.
Sometimes it’s difficult for a computer to count syllables accurately, so the measures are sometimes not 100% precise, but from a practical point of view that doesn’t matter.
There are two basic types of measures. The first is just a score, which doesn’t mean much by itself, but can be used to compare one piece of writing to another.
The second measure, which Flesch and Kincaid developed, and several others have followed, is more useful to us. It shows the average American school reading grade needed to understand your writing.
What are the most popular readability scores?
There are several readability tests that ultimately boil down to a US reading grade. This means that we can run several tests, compare them, and take the average.
Here are the big guns of the readability index world. They all work in different ways, and the links below take you to Wikipedia articles so you can find out more. They produce results of a US reading grade that are usually no more than two or three grades apart.
(Readability Score gives you these links when you see your results, which is nice.)
- Flesch-Kincaid Grade Level
- Gunning-Fog Score
- Coleman-Liau Index
- SMOG Index
- Automated Readability Index
- Spache Score – not particularly useful because it’s designed for writing aimed at children up to fourth grade. It can produce results way out of line with other methods, as you can see from the screenshots in this article.
- Dale-Chall Score – interesting because it contains a list of 3,000 words that American fourth-graders can understand, and considers any other words to be difficult.
How does readability-score.com work?
This website was built and maintained by Dave Child, who’s based in the UK. I don’t know him personally, but he’s very friendly and responsive to email, if you have feature requests, etc.
The site is nice and easy to use, and looks good. You can either paste some text directly into the site (which is what I do), or upload files, or point the site to a URL web link that contains your text. The site can even monitor your links, such as your homepage, and alert you when certain readability thresholds are breached.
The results are very clear and easy to see, and I’m sure you’ll find it very useful.
You get to see the various reading grade levels for your writing, and an average.
You also get keyword density, ie how often certain words or two-word phrases appear. Personally I don’t need this, but if you write with SEO in mind it can be helpful.
Word count, sentence count, and average words per sentence are useful. I’ll give you some recommendations below for how you could use this.
The longest sentence is a crucial metric, and one that I asked the site author to add for me. (Impressively he added it within a day!) You also get the longest word, which can be helpful too.
If you are more than a casual user, there are very reasonably-priced subscription options, which help support the site.
How to use readability scores in your writing
Even highly intelligent and/or educated people (not always the same thing!) find it easier to read and comprehend writing that is at a lower reading grade. So no matter who you are writing for, whether it’s doctors and lawyers, manual workers, or the fabled “high-school dropouts”, a lower score is usually better.
It contains these facts from the Literacy Project Foundation, relating to American readers:
50% of adults cannot read a book written at an 8th grade level
45 million are functionally illiterate and read below a 5th grade level
In other words, the average reading grade in America is 8th grade level. I have no particular reason to doubt that the UK is very similar.
The advice of Denny Hatch, which I agree with, is:
- Keep sentences to 29 words or fewer
- Write at 8th grade level or even lower if you can
Conclusion: an essential site for all writers
Here’s a screenshot showing the readability scores for this very article you’re reading now. (Click the image to see a larger version.) What do you reckon? Must try harder!