Readability scores

The table on the last page used the Automated Readability Index, one of several formulas that turn a page into a US school grade. Before the next lesson looks at a tool for the words themselves, it is worth knowing why we are not chasing that grade.

Caroline Jarrett and Ginny Redish set out the case in Readability Formulas: 7 Reasons to Avoid Them and What to Do Instead (opens in a new tab) (UXmatters, 2019). Their 7 reasons, in short:

1. Different formulas give different scores for the same text
2. A score cannot measure whether the reader actually understood it
3. Formulas count syllables, not whether the reader knows the word ("wave" scores the same as "waive")
4. A US school grade means little for an adult with reading difficulties, who often has plenty of life experience and vocabulary
5. Formulas assume full paragraphs. They cannot judge a form, a list, or an ecommerce page
6. Shortening sentences and swapping in shorter words treats the symptom, not the cause
7. A good score does not guarantee the content is useful or usable

Their advice instead: write for your actual audience, follow clear writing guidelines, and test with real readers. That is the approach the rest of this chapter takes, and why Dawn, the tool in the next lesson, gives you specific points to look at rather than a score to chase.

📝 Have you ever changed a piece of text just to improve its readability score, at the cost of making it read worse? Share what happened in the discussion.