A few months ago, a colleague of mine commented that she preferred to read copy that was “less detailed” than mine, because less focus and concentration were involved. “Shortness sells,” she quipped, half jokingly, rewriting the age-old writer’s adage that “specificity sells.”
But that moment stayed with me, since most writers are neurotic about the effectiveness of their writing and because it is not specificity per se (or brevity) but precision that should win the day.
To answer my colleague, I’d say that yes, brevity can be useful, but unless we’re talking about aphorisms and taglines or other hard-core, digital marketing, brevity won’t sell. 
One of my favourite copywriters, Henneke Duistermaat, recently blogged on why longer-form copywriting is useful—the form in which I have specialized for the past 10 years (e.g. writing blog postings, articles, media releases, case studies, website copy, etc.).
Length, when written well, can be more precise, vivid and, in her words, “full of zest” than its shorter counterpart. “Even if your text becomes longer,” Henneke writes, “precision captivates readers.”
Business-to-Business copywriting (B2B) is a good example of this, as it is often longer than its Business-to-Consumer (B2C) counterpart. The former features more detailed content and research.
The non-writerly colleague I mentioned at the outset of this post disputes the need for detail in business writing. I certainly strive to avoid long, rambling, boring writing. But I disagree that detail means doldrums. Writing should not aim to be brief, but sufficiently long to express its insights and engage its audience. As Henneke comments: “Brevity can suck the spirit out of your writing. Writing that’s too brief is soulless. It lacks the power to engage and inspire.” 
In a recent blog posting on her website, Duistermaat shows what short copy can lose, when she cites a seven-word, newspaper description of American Arthur Ashe’s serve in tennis:
“Arthur Ashe started the match on serve.”
By contrast, she cites a 165-word depiction of that same serve, written by Pulitzer prize-winning journalist, John McPhee:
Arthur Ashe, his feet apart, his knees slightly bent, lifts a tennis ball into the air. The toss is high and forward. If the ball were allowed to drop, it would, in Ashe’s words, “make a parabola and drop to the grass three feet in front of the baseline.” He has practiced tossing a tennis ball just so thousands of times. But he is going to hit this one.
His feet draw together. His body straightens and tilts forward far beyond the point of balance. He is falling. The force of gravity and a muscular momentum from legs to arm compound as he whips his racquet up and over the ball.
He weighs a hundred and fifty-five pounds; he is six feet tall, and right-handed. His build is barely full enough not to be describable as frail, but his coordination is so extraordinary that the ball comes off his racquet at furious speed. With a step forward that stops his fall, he moves to follow.
The precision of McPhee’s depiction of how Ashe serves, the statistical detail it includes of Ashe’s size, the reference to his previous practice and so on, all elicit readers’ interest and pull us into the story. As Henneke says, “When you read McPhee’s description, you feel like you’re on court watching the match unfold.”
Precision (rather than unwieldy length) is also better at eliciting the reader’s emotion. The detail of the above sample is persuasive and intensifies its drama.
And through these qualities, the writing also makes the writer (i.e. McPhee) more credible. We sense that McPhee is an expert about tennis and understands the significance of the performance he’s describing.
Now not all writing can provide such detail. Henneke observes that writing must cycle between an “ebb and flow,” or else it will risk being long-winded. But the alternative to that is not (or not only) brevity. 
But when length coincides with precision and all of its ensuing power, we all (as writers) become more likely to serve a winner.
And now it’s your turn. Do you agree that precision can make longer-form copy more powerful than its shorter counterpart? Please include your samples! I’d be delighted to hear from you