Overview

Why this framework exists

Bly distills decades of writing advice into four ruthlessly simple principles: use short words, write short sentences, keep paragraphs short, and break copy into short sections. Research shows that comprehension drops dramatically when sentences exceed 34 words, and that the ideal average sentence length for business writing is 14-16 words. Ad copy should average even shorter. Big words do not impress; they annoy and obstruct. The formula applies to all persuasive writing because you cannot sell to someone who does not understand you. As the Harvard Business Review confirmed, advertising is most effective when it is easy to understand.

Core principles

5 total

Comprehension and persuasion both collapse when sentence length climbs above what working memory can hold.
Short words serve the reader; long words serve the writer's ego.
Simplicity is not dumbing down but clearing away everything that slows the transfer of meaning.
You cannot sell to someone who is still decoding your sentences, so clarity always comes before cleverness.
Every additional word is a small tax on the reader's attention, so every word must earn its place.

Steps

4 steps

Replace big words with small words
Audit your copy for polysyllabic words and replace them with simpler alternatives. 'Utilize' becomes 'use.' 'Procure' becomes 'get.' 'Terminate' becomes 'end.' 'Perspiration' becomes 'sweat.' As Hemingway said, there are older, simpler, and better words. Even Shakespeare's most famous sentence uses no word longer than three letters.
Break long sentences into shorter ones
Target an average sentence length of 14-16 words. Split any sentence over 34 words into two or more sentences. Use punctuation (dashes, ellipses, colons) to divide complex ideas. Vary sentence length for rhythm: follow a long sentence with a very short one. Even sentence fragments are acceptable in copy.
Keep paragraphs short and break up blocks of text
No paragraph should exceed five sentences. Three to four sentences is ideal. A page filled with solid text says 'this is going to be tough to read.' Find the natural break points where new thoughts begin and start new paragraphs. Leave space between paragraphs.
Divide long copy into labeled sections
Use subheads, numbered lists, bullet points, and other visual devices to break long copy into discrete, scannable sections. If points follow a logical sequence, use numbers. If there is no particular order, use bullets or dashes. Subheads allow readers to jump to sections that interest them and also draw the eye through the text.

Examples

1 cases

The bank brochure buried offer

A Midwest bank wanted to know if customers read their brochures. They buried an offer for a free ten-dollar bill in a paragraph within 4,500 words of dense, technical text. Not a single customer claimed it. This demonstrated that poor organization and dense, unbroken text effectively hides information from readers. Had the bank used the 4 S principles with short sections, subheads, and a prominent call-out for the free money offer, many customers would have found and responded to it.

OutcomeThe experiment proved that writing quality and structure directly impact whether readers engage with or ignore your content. Dense, unstructured copy is functionally invisible regardless of how good the offer is.

Common mistakes

2 traps

Using big words to sound authoritative or sophisticated

Bly is emphatic: pompous language does not impress readers. It annoys them and obscures your message. A Unitarian minister saying 'eternalize evil' instead of 'make evil last forever' loses his congregation. Copy should be like windows in a storefront: the reader should see right through the words to the product.

Making all sentences the same length

While the average should be short, copy where every sentence is identical in length becomes monotonous and rhythmless. The trick is to vary sentence length, using occasional very short sentences or fragments to create snap and emphasis, while keeping the overall average within the recommended range.

Origin story

How this framework came to be

Bly distills decades of writing advice into four ruthlessly simple principles: use short words, write short sentences, keep paragraphs short, and break copy into short sections. Research shows that comprehension drops dramatically when sentences exceed 34 words, and that the ideal average sentence length for business writing is 14-16 words. Ad copy should average even shorter. Big words do not impress; they annoy and obstruct. The formula applies to all persuasive writing because you cannot sell