The Science of Writing

Jack Williams - Account Executive

Jack Williams – Account Executive

Whether you consider writing an art, or speak of it as a craft (or perhaps you refer to it as a calling, in which case I’d stop that), there are some formulae we can use to analyse and score our writing. Unfortunately, this isn’t a formula for classically great writing. Instead, these are mathematical formulae that can help determine the readability of a piece of text.

There are a number of statistics we can use to determine readability and through Word we have easy access to two of them. On behalf of Writers Inc. I’ve compiled a brief overview of these techniques, what they mean to our writing and how we can use them.

Flesch Reading Ease (FRE)

This first method rates our text on a 100-point scale and was created by author and readability expert Rudolf Flesch. It takes into account sentence length and number of syllables per word. The general idea is that long sentences and big words are harder to read.

If you want to work out the FRE score of your writing, the long way to do it is use the following formula:

FRE = 206.835 – (1.015 x ASL) – (84.6 x ASW)

ASL = average sentence length

ASW = average syllables per word

Rudolf Flesch

The quick way is to switch readability on in Word and I will explain how to do this further on.

With this method, the higher we score after inputting all the figures, the more readable the text is. Most standard documents should be aiming for a readability score of approximately 60 to 70.

Flesch-Kincaid Grade Level (FKGL)

Again developed by Rudolf Flesch, this method is almost the inverse of FRE in that a low score indicates good readability. It also works by analysing sentence and word length. The score you are given is then roughly translatable to an American high school grade. For example, a score of 7.0 means that a seventh grader, or a year 8 in the UK, would be able to understand the text. Under this test, to achieve plain and simple writing, we are aiming for a score between 7.0 and 8.0. This translates to between year eight and year nine. Or, can be understood by an average 12 to 14 year old.

The formula of this equation is:

FKGL = (0.39 x ASL) + (11.8 x ASW) – 15.59

How should we use this in our writing?

As professional communicators, our words should always be plain and simple because it’s important the audience understands us.

Einstein's Communications advice

However, the truth about these tests is that they are guides at best; while the scores they throw up give an indication of readability, they should not be taken as gold. The only thing they do explicitly tell us is the average length of sentences and average number of syllables each word has in a given text.

Again though, taken as guides, these are useful tools in the copywriter’s handbook.


As a comparison, an article from the Guardian on the Grangemouth plant, which is facing closure in Scotland, scored a FRE score of 42.3 and FKGL of 13.8. Its opening paragraph reads:

“Union leaders are to meet managers at the Grangemouth petrochemicals site in Scotland in a bid to save thousands of jobs after its owner abruptly closed the plant in a bitter industrial dispute.”

Daily StarOn the other hand, the Daily Star’s take on Wayne Rooney and his denial of handing in a transfer request scores 76.6 on the FRE scale and 6.0 on FKGL. Its first paragraph is:

“At the end of last season, Fergie alleged Rooney had asked to quit United because he was unhappy at Old Trafford.”

The Guardian is aimed at a more business-focused audience than the Daily Star and is discussing a much more complex, serious subject. It is completely appropriate for it to score higher on these readability scales. Yet, the difference in their opening sentences is stark.

How to set up readability

Both FRE and FKGL are accessible quite easily in Word. In the latest version of Word (2013), do the following:

  • Click the File tab, and then click Options
  • Click Proofing
  • Under ‘When correcting spelling and grammar in Word’, make sure the ‘Check grammar with spelling’ check box is selected
  • Select ‘Show readability statistics’
  • After you enable this feature, open a file that you want to check and check the spelling. When Outlook or Word finishes checking the spelling and grammar, it displays information about the reading level of the document.

Instructions for toggling readability statistics in other versions can be found here.

A bonus readability score

Although I said Word only gave us access to two readability formulae, it does provide another useful tool for determining readability. ‘Passive Sentences’ under readability statistics provides the ratio of passive sentences over active sentences.

As writers we should avoid passive sentences where possible, as they are more difficult to follow and understand. Plus, they can increase the word count unnecessarily.

Yet, once again, this is not a hard and fast rule and as communicators we should be deciding when a rule is worth following and when not.

Except apostrophes. That rule is non-negotiable.

Need advice or professional proofreading services? Writers Inc. can help.

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