I often hear this question. The answer depends on what you are trying to accomplish.
One of the hot topics is storytelling. When I was leading the Ohio brand, we designed a campaign to leverage the power of storytelling to promote the State for capital investment. We leaned into the principles espoused by Joseph Campbell in his book - The Power of Myth. This is a book I would encourage anyone interested in marketing to read.
We built the campaign on the insight that C-Suite Executives find their peers to be highly credible sources of information. That led us to communicate the Ohio brand promise by telling the stories of CEOs who have experienced it first-hand. The State Of Perfect Balance Campaign was born.
The storytelling approach requires a longer copy format to work well. The story is used to capture a reader's attention and interest. The benefit copy at the bottom of the advertisement creates a reader's desire to call a toll-free number or visit a website for more detailed information about the State’s assets.
The headline, body copy, CEO quote, website name, and " sign-off” provide strong visual elements to support the brand. Even if the reader simply skims the advertisement, it is clearly recognized as being about Ohio.
The Ohio brand promises you and your employees a successful career and a fulfilling life in Ohio. This campaign drove Ohio to national leadership in the number of large capital investment projects, so it was highly effective. I am not certain it would have been as effective in communicating the Ohio brand promise if limited to a short format. I have often found that complex purchase decisions require more information than simpler decisions. In this case, providing more information about why a CEO should consider risking capital to build or expand a facility in Ohio made perfect strategic sense.
From my experience, I pay the most attention to these eight keys to great print advertising.
Relevance of Message. You cannot communicate your message to the reader if the copy is irrelevant.
Stopping Power. If the reader doesn’t stop to look, your advertisement will not be read, regardless of the length of the copy.
Benefit Focus. Readers subscribe to the WIFM broadcast channel. They look at advertising copy from a What’s In It For Me paradigm.
Strategic Alignment. Visuals and copy should be mutually reinforcing and not at odds.
Clear Call to Action. Readers need to know what to do to get the benefit you promise.
A campaign idea is built on an Insight. If it is to be interesting and compelling, the copy should leverage a unique insight into the reader’s mind or heart.
Prominent branding is essential if you want readers to remember your message. They must see your brand mark and understand your promise.
Visual Appeal. If your gut doesn't feel great about the advertisement, your readers won’t feel good about it either.
I hope the above provides you with some practical perspective regarding the best length for print advertising copy.