Contractions

Last updated: 20 December, 2019

Following this helps people with:

time pressures: when reading quickly it's easy to misunderstand
stress: high anxiety levels make it harder to comprehend things
multi-tasking: when distracted you might misread things
cognitive impairments: spelled out words are less of a strain

Guidelines

Many organisations encourage using contractions, as they make content more conversational. Others are reluctant to because of the informal tone. We're mainly concerned with usability. Some types of contractions cause issues.

1. Avoid negative contractions.

2. Simple positive contractions may be fine.

3. Possessive nouns, which are read in a similar way to contractions, may be fine.

4. Avoid conditional contractions.

Usability evidence

1. Avoid negative contractions.

Like shouldn't, can’t and don’t. Research shows that many users:

find negative contractions difficult to read
misread them as the opposite of what they say

2. Simple positive contractions may be fine.

Like: you'll, we'll, we're, they're, it's, I'll, there'll, there's.

We have not found any existing usability studies that show positive contractions cause or do not cause difficulties for users. We would like to test this with users.

3. Possessive nouns, which are read in a similar way to contractions, may be fine.

Like "my organisation's ethos", "your cat's tail", "the suitcase's weight".
There's no usability evidence against possessive nouns at the moment. We would like to test this with users.

While we're here, use "its", without an apostrophe, for possessive nouns. For example "its ethos".
And "it's", with an apostrophe, to shorten "it is". For example "it's sunny".
That's not a readability guideline, just a grammar point.

4. Avoid conditional contractions.

Examples: should've, would've, could've.

People with cognitive challenges or a low literacy level find less often used, complex tense contractions like these hard to recognise and understand.