The information in this blogpost may now be out of date. See the current GOV.UK content and publishing guidance.
We recently blogged about our checklist for reviewing content and got a lot of questions about sentence length.
The Service Design Manual explains how people read and why sentences longer than 25 words aren't accessible.
In the style guide we’re now saying that if you have sentences longer than 25 words, try to break them up or condense them. If you can’t, make sure they’re in plain English.
When you write more, people understand less
GOV.UK should be an authoritative, trusted source. This means we need to write in a way everybody understands. We know people distrust jargon and that being clear and direct helps - as do shorter sentences.
Writing guru Ann Wylie describes research showing that when average sentence length is 14 words, readers understand more than 90% of what they’re reading. At 43 words, comprehension drops to less than 10%.
Studies also show that sentences of 11 words are considered easy to read, while those of 21 words are fairly difficult. At 25 words, sentences become difficult, and 29 words or longer, very difficult.
People don’t read
Long sentences aren't just difficult for people who struggle with reading or have a cognitive disability like dyslexia or attention deficit hyperactivity disorder. They're also a problem for highly literate people with extensive vocabularies.
This is partly because people tend to scan, not read. In fact, most people only read around 25% of what’s on a page. This means it’s important to get information across quickly.
If it’s complex, make it simple
Long, complicated sentences force users to slow down and work harder to understand what they’re reading. This isn’t something people want to do, even if they’re familiar with the subject or language you’re using.
It’s easy to assume this isn’t the case for highly literate readers or people considered experts. Yet the more educated a person is, and the more specialist their knowledge, the more they want it in plain English.
These people often have the least time and most to read. Which means they just want to understand your point and move on, quickly.
Cut through the noise
It’s also important to think about how people access your content. They might be in a busy office, fighting for space on a crowded train or peering at their mobile in bed.
They don’t have time to deconstruct sentences and contemplate clauses, they just want you to get to the point. Doing this shows you respect your reader’s time, interest and attention.
If you write short sentences using plain English, it’ll help more people understand your content. And by making it more accessible, you won’t just help your busiest readers, you’ll open it up to people who might otherwise struggle to understand it.