Using Ordinal Numbers? Read This First!

Alt: A group of doodles with cat head are watching the news. The news anchor says, “Breaking! Out of all 99,999 cases of people with cat head, Eustace Dander is the VERY FIRST to be cured!” One doodle shouts, “Can I be second?!”

Here at We ❤ Health Literacy Headquarters, we ❤ a good, clear rule or best practice. You should know, dear readers, since we often share them with you! But the thing about rules is that they always have exceptions — and today we want to talk about one of those.

We’ve told you before that writing numbers as numerals is generally the way to go in plain language materials. So what’s the exception, you ask? Ordinal numbers! (And if you need a refresher on what exactly an ordinal number is, no worries — it’s coming.)

When you use numbers in health writing, you’re often describing an amount. For example:

  • 3 doctors
  • 1 in 10 children
  • 33 people with cat head

But when you use ordinal numbers, you’re describing the position of something. For example:

  • Second leading cause of death
  • Sixth round of treatment
  • First person to fully recover from cat head

In those examples you’re not describing an amount, so using the numeral might be confusing to readers who are quickly scanning text — as we know folks are likely to do. That’s why, in general, we choose to spell out ordinal numbers under 11.

Certain platforms and word processing systems can also make ordinal numbers harder to read when you go with the numeral approach. Try typing “2nd” into Microsoft Word, for example. Does the “nd” automatically change to superscript? Superscript might be too small for readers to easily see. And we don’t know about you, but we find it a bit distracting.

Disclaimer: this rule (or exception, rather) is a product of our informed opinion, not user testing. But try it out — your readers just might thank you!

The bottom line: Part of clear communication is making text easy to look at, so take it easy on your readers’ eyes and spell out ordinal numbers under 11.

Tweet about it: Spelling out ordinal numbers can make ’em easier on the eyes, says @CommunicateHlth: #HealthLit


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