Readability is an attempt to match the reading level of written material to the “reading with understanding” level of the reader.
There are a number of tools that can help you to appraise written text for readability by applying a standard formula to selected text. All readability tools rely on a very rough gauge of the level of reading people have acquired by a certain point in their lives. But successful reading is about far more than word recognition – it’s about other factors such as style, physical presentation, and readers’ interest, confidence and skill.
Readability tools are a subject of debate in the field of plain language – some people view them as a useful starting point when assessing the clarity of information, others as a tool that encourages poor writing. In general, readability formulae should only be used as a guide because they do have limitations.
They can be helpful in objectively analysing what you have already written and are also good for comparing several different documents, or different versions of the same document. Readability formulae can also show your reviewers whether any changes they make to the text are really making it clearer.
However, readability tools only look at language; they do not take into account the tone of the information, the structure, or the layout and design. They measure text crudely and you will get the same score whether a sentence is written backwards or forwards. There is also no guarantee that a short sentence will be understandable. A gut instinct for how the information reads and asking for comments from patients will be more useful than relying solely on readability formulae.
Applying different readability tools to the same piece of text will also give you different scores and different reading levels. The results of testing therefore depend significantly on which tool is used. The main Readability Tools are Flesch-Kincaid Index, Fry Formula Gunning FOG Index and SMOG (Simplified Measure Of Gobbledygook!). You can also use text editing software. Word-processing packages often contain what are claimed to be grammar checkers that will assess text for possible errors in grammar and suggest alternatives. These tend to be of dubious merit. There are also more sophisticated programmes, such as Stylewriter, which apply readability formulae to specified text and usually show readability statistics as numerical scores.
- Readability tools are often criticised for not predicting the true reading ease of a piece of text, and there are a number of things they can’t tell you, such as whether:
- the content is good – whether it’s accurate for example
- the text is logically arranged and easy to navigate
- grammar and punctuation are correct
- the text includes personal reference words, like you and we, which make it accessible
- the presentation is appealing.
- Text may score well when put through a readability tool, but it can still be meaningless, inaccurate or misleading. Although there is evidence to show that most people understand more when words and sentences are short and simple, it is also true that long words and sentences are not always difficult to understand and short words and sentences are not always easy to understand.
- Never use readability tools alone. They should be only one of the methods used to assess information for quality, readability and accessibility.
- There are a number of organisations that can assess your publications for clearly written understandable English, which includes design and layout. The two main ones in the UK are the Plain English Campaign and Plain Language Commission.
- Some readability tools display the readability of a document as an American grade-level (year of school) so remember that children start school in America at the age of six, rather than four or five as in the UK. You can convert the American grade level to the British reading age by adding five to the final readability score.