Sentence length one of top 2 predictors of readable copy
“Anyone who finds himself putting down several commas close to one another should reflect that he is making himself disagreeable and question whether it is necessary.”
H.W. Fowler, English lexicographer
A professor of English Literature at the University of Nebraska was the first person to link sentence length to comprehension.
In the 1880s, Lucius Adelno Sherman took the first statistical look at writing when he calculated sentence length in historical literature. In his book, The Analytics of Literature (1893), he shared how sentences were growing shorter over time:
- Pre-Elizabethan times: Sentences averaged 50 words
- Elizabethan times: 45 words
- Victorian times: 29 words
- Sherman’s own time: 23 words
Today, sentences average 20 words, reports readability expert William H. DuBay in Unlocking Language (PDF).
In the 130 years since Sherman started counting words per sentence, dozens of other researchers have proven what Sherman posed: Shorter sentences make for easier reading.
Indeed, DuBay writes, sentence length and word length have been proven in the lab — again and again — to be the two strongest indicators of reading ease.
Write sentences to be read.
Bottom line? To make your copy easier to read and understand, the studies show, write sentences that are:
And reduce the number of:
- Dependent, embedded and other clauses
- Phrases per sentence
- Words before the verb
How do you keep your sentences short and easy to understand?