I didn’t have time to write a short letter, so I wrote a long one instead.
Readability is about how easy something is to read. The rules are obvious:
- Avoid fancy words and jargon where possible
- Use simple, coherent sentences
- Use correct grammar, punctuation, and spelling
- Make the text skimmable by giving it visual clarity
The hard part isn’t understanding the rules. It’s following them. Readable writing is less about what it is and more about what it isn’t.
Readability formulas calculate how readable a given text is. There are a lot of them. They’re cold and unyielding, spelling the rules out as clear as day. Bad writers don’t like them.
The most useful one is the Dale–Chall readability formula. It’s based on the Flesch–Kincaid readability tests, but uses the percentage of difficult words instead of the average number of syllables in its calculation. This is an obvious improvement, but before computers made the calculation take too long.
Critics of readability formulas mainly focus on how they oversimplify things. This is true, but also misses the point:
One popular misconception is that, because of readability formulas, publishers are watering down their textbooks, creating artificial language because certain words on the graded word lists cannot be used. In fact, no word list nor any formula tells authors and publishers which words should not be used. Guides that exist are based on usage only at the time the guides were developed, and so change with time.
Another misconception, venerable but increasingly popular, is that readability formulas do not measure all of readability. Researchers in readability have consistently acknowledged [that at best], readability formulas give only predictions of readability. The ultimate test of difficulty is a tryout or field test with readers for whom the material is intended.
Still another persistent misconception is that formulas can be used on any text. Actually, each formula can be used only for testing the kinds of materials on which it was standardized.
Business writing is about clarity and persuasion. The main technique is keeping things simple. Simple writing is persuasive. A good argument in five sentences will sway more people than a brilliant argument in a hundred sentences. Don’t fight it.
Simple means getting rid of extra words. Don’t write, “He was very happy” when you can write “He was happy.” You think the word “very” adds something. It doesn’t. Prune your sentences.
Humor writing is a lot like business writing. It needs to be simple. The main difference is in the choice of words. For humor, don’t say “drink” when you can say “swill.”
Much of this page is from The Principles of Readability by William H. Dubay, 2004, a detailed but concise (and readable!) dive into readability research.