It’s no more than coincidence that on Proust’s birthday, Bryan Garner’s Usage Tip of the Day concerns sentence length. An excerpt:
What is the correlation between sentence length and readability? No one knows precisely. Rhetoricians and readability specialists have long suggested aiming for sentences of varying lengths, but with an average of about 20 to 25 words. And empirical evidence seems to bear out this rough guideline.Ted Berrigan once said in an interview that a little man in the back of a poet’s head manages rhyme and meter. I think that the little man’s little brother manages sentence length in prose. In other words, I find it difficult to imagine variety in sentence length as the product of conscious effort.
In 1985, three authors calculated figures for several publications, using extensive samples. Average sentence length ranges from about 20 (Reader’s Digest ) to 24 (Time ) to 27 (Wall Street Journal ). They arrived at a provocative conclusion: “Varying your sentence length is much more important than varying your sentence pattern if you want to produce clear, interesting, readable prose.” (Gary A. Olson, James DeGeorge & Richard Ray, Style and Readability in Business Writing 102 (1985)). If you’re aiming for an average sentence length of 20 to 25 words, some sentences probably ought to be 30 or 40 words, and others ought to be 3 or 4. Variety is important, but you must concern yourself with the overall average.
The averages that Garner cites made me curious enough to look at sentences of my own. In a review of David Foster Wallace’s unfinished novel The Pale King that I wrote last year (for World Literature Today, a print publication), the sentences average 28.1 words. The longest sentence: 47 words. The shortest: 12. The little man’s little brother was hard at work: the shortest sentence comes right after the longest. In a review of Christopher Lasch’s Plain Style that I wrote as a blog post last month, the sentences average 28.6 words. The longest sentence: 74 words. The shortest: 4. And in a post last week on Alan Paton’s Too Late the Phalarope , the sentences average 18 words. Once again, the longest sentence (33) and the shortest (9) appear one next to the other.
Student writers are often wary of long sentences, sometimes because of uncertainty about punctuation (any longish sentence must be a “run-on”), sometimes because of poor teaching. And short sentences seem even more dangerous (because short must equal “dumb”). But variety in sentence length is of course a good thing. Even Proust has short sentences. One of them begins Du côté de chez Swann: “Longtemps, je me suis couché de bonne heure.”
[Bryan Garner, author of Garner’s Modern American Usage (2009), offers a free Usage Tip of the Day. You can sign up at LawProse.org. Orange Crate Art is a Garner-friendly site. The first sentence of Swann's Way in Lydia Davis’s 2002 translation: “For a long time, I went to bed early.” The free Mac app TextWrangler made the work of counting sentences and words no work at all.]