NEW YORK: A new study from the Advertising Research Foundation (ARF) has claimed to offer "definitive" proof that advertising works.

Released to coincide with the organisation's annual Re!Think event, the research was based on more than 5,000 campaigns, 12 years of data and $375bn in advertising spend in 41 countries, across more than 100 categories.

There has not been a study done to this scale and depth in over 25 years, the ARF said of How Advertising Works Today, which was sponsored and supported by over 25 contributing companies including ESPN, CBS, Unilever, Kellogg, Levi's, Nissan, Facebook, Google, Millward Brown, Nielsen, and comScore.

"This research definitively proves that advertising works," it declared.

Among the insights revealed by the study were the fact that marketers may be damaging growth by not investing enough in advertising as they shift the mix from traditional to new platforms, so missing the opportunity to generate billions in additional return.

Spending across multiple platforms was also shown to deliver greater ROI than any single platform – including for millennial consumers.

The flip-side of that was "silo-investing" – where too much frequency via a single platform may lead to diminishing returns.

Overall, a unified creative strategy across platforms was said to be the key to compounding the investment of a multi-platform campaign. But, the study added, unified creative executions also need to be specifically tailored to each platform to ensure optimal consumer engagement.

Marketers can also jump-start growth by taking advantage of the "kicker effect" of smart spending with specific combinations of traditional plus new media on the right platforms.

"We are pleased to lead this important initiative that brings scientific proof, measured opportunities and a roadmap for growth to the industry at C-suite speed and scale," said Gayle Fuguitt, CEO and President of the ARF.

Data sourced from ARF; additional content by Warc staff