Assessing readability

Communication and Health Literacy

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Main point

Edit, proofread, use a readability assessment tool and then get feedback from your audience.

Edit and proof-read your document

It is important to edit, then proof-read your document before assessing readability.

If you are not a professional writer, ask a professional editor or communications advisor to edit your document. If you edit your own document, try to leave it a few days first.

To proof-read your document, read it out loud or ask a colleague to check it.

Use a readability assessment tool

For most consumer-focused resources, aim for Reading Grade 6 (typically ages 11–12 years).

While it's important to check readability, don't get hung up on readability scores. Word and sentence length are just two of more than 100 factors that affect reading ease.

Flesch Reading Ease/Flesch-Kincaid Grade Level

This is a basic assessment tool in Microsoft Word. In Word, highlight the text you want to assess, go to Review tab, select Spelling and Grammar, then Options, then tick the option for showing readability statistics. With this ticked, the Flesch-Kincaid Grade Level will be shown after the spelling and grammar check.

Research has found that SMOG (see over the page) may be a better tool for readability.1

Simple Measure of Gobbledygook (SMOG)2

SMOG calculates reading grade on two factors: the number of syllables in words and the number of words in sentences. There are online tools2 for calculating SMOG, or calculate your own:

Step 1: Count 10 sentences in a row near the beginning of the text to be assessed, 10 in the middle and 10 at the end for a total of 30 sentences. Select blocks of text that do not have lengthy names, email addresses or complex contact details.

Step 2: Count every word with three or more syllables in each group of sentences.

  • Treat long sentences split by semi-colons as two sentences, hyphenated words as single words and abbreviations as though they are unabbreviated.
  • Include proper nouns (names and titles).
  • Treat numbers written as numerals as if they are in written form.

Step 3: Calculate the square root of the number arrived at in Step 2 then add three. That will be the reading grade a person must have reached to fully understand the text.

Online Tools

There are a range of online tools you can find to help you work out readability.  One you might find useful is the Hemmingway Editor app3 which checks words, sentences, as well as active voice and strength of phrasing.  Paste in something you ae working on and edit away.

Get feedback from your target audience

Remember who you are writing your resource for and include them.  Test your resources with consumers.  Ask them if the document is clear, what message is it getting, if it gives them what they need to know.  Check for different ways of getting the information across.


1. Grabeel KL et al, Computerized versus hand-scored health literacy tools: a comparison of Simple Measure of Gobbledgook (SMOG) and Flesch-Kincaid in printed patient education materials. J Med Libr Assoc. 2018 Jan;106(1):38-45. Doi10.5195/jmla.2018.262 Epub 2018 Jan 2.

2. WordsCount, WordsCount, 2009, viewed 21 July 2014, www.wordscount.info/index.html

3. www.hemingwayapp.com/

January 2019