Gary Provost's Masterclass in Sentence Length
In 1985, author Gary Provost wrote what is arguably the most famous paragraph on writing technique ever penned:
"This sentence has five words. Here are five more words. Five-word sentences are fine. But several together become monotonous. Listen to what is happening. The writing is getting boring. The sound of it drones. It's like a stuck record. The ear demands some variety.
Now listen. I vary the sentence length, and I create music. Music. The writing sings. It has a pleasant rhythm, a lilt, a harmony. I use short sentences. And I use sentences of medium length. And sometimes, when I am certain the reader is rested, I will engage him with a sentence of considerable length, a sentence that burns with energy and builds with all the impetus of a crescendo, the roll of the drums, the crash of the cymbals—sounds that say listen to this, it is important."
This passage is the ultimate definition of burstiness.
How AI Fails the Provost Test
When an AI writes, its internal probability engine tends to generate sentences that hover between 15 and 22 words. It rarely writes a 2-word sentence ('Now listen.'). It rarely writes a 45-word cascading crescendo.
Because the variance (standard deviation) is so low, readers feel tired after just two paragraphs without knowing why. Their eyes glaze over.
Decoding the Flesch Reading Ease Index
Flesch Reading Ease is a standard readability formula calculated using two simple variables:
1. Average Sentence Length (words per sentence)
2. Average Syllables per Word
The formula scores text from 0 to 100:
• 90–100: Very Easy (5th-grade level, conversational comics)
• 60–80: Standard & Engaging (8th–10th grade, ideal for blogs, SaaS landing pages, and work emails)
• 30–50: Difficult (College-level academic papers, legal terms)
• 0–30: Extremely Dense (Scientific journals, insurance policies)
Unchecked AI text almost always falls into the 30–50 range because it defaults to polysyllabic Latinate terms ('comprehensively', 'facilitate', 'methodology'). Good human editing pulls it back up into the comfortable 65–75 zone.
Practical Exercises to Increase Burstiness
• The 3-to-1 Rule: For every three medium sentences, force yourself to write one sentence with four words or fewer.
• Cut prepositional chains: Change 'The implementation of the system by the development crew' to 'The dev team launched the system.'
• Read aloud with a pencil: Anywhere you trip or stumble, split the sentence in half.
• Use our live workbench at aitext.tech: Watch the burstiness score update live as you edit!