Plain English is when a reader can find, understand and use the information they need from a piece of communication. Plain English includes a range of elements such as the use of everyday words instead of jargon and legalese, and short, active sentences instead of long-winded passive sentences. But plain language isn’t only about words and grammar. How well a document or website is structured, how easy it is to navigate, the visual design, and the usefulness and relevance of its content all form part of plain English.

According to the Center for Plain Language (US), `plain language for one audience may not be plain language for another audience´: Plain language is when the audience for the material can quickly and easily:

• Find what they need
• Understand what they find
• Act appropriately on that understanding.

You can learn more about ´what is plain English´ at Clarity, a worldwide network of professionals who are committed to promoting plain legal language.

What are readability tests?

Readability tests focus on linguistic elements such as the active voice, short sentences and everyday words. Although these elements are building blocks to good communication, they are not enough. To assess clarity and plain language, you have to also consider factors such as:

• The existing knowledge the reader has about the topic
• Whether the purpose is clearly set out
• Structure of information
• Prominence and ´findability´ if the content is online
• Completeness of information
• Format and style
• Design and layout

Common readability formulas include Flesch–Kincaid readability tests and the Gunning fog index. In short, while readability tests can help you to filter out really bad communication, they don´t do well in telling you what your readers actually will or will not read, understand and use. For that, you need a full user-testing programme.