As artificial intelligence becomes increasingly embedded in the way advertising is bought, priced and delivered, Chief Marketing Officers (CMOs) will need to place greater emphasis on strategic platform selection, transparency and independent measurement, according to Gartner.
Gartner estimates that by 2028, more than 70% of global advertising spend and 80% of advertising spend in the U.S. will flow through self-serve advertising platforms where AI materially influences media buying, costs and outcomes.
The growing role of AI extends beyond the creation of advertising content. While generative AI is increasingly being used to develop creative assets, advertising platforms are deploying AI behind the scenes to determine which advertisements are shown, which audiences are targeted, how campaigns are delivered and, ultimately, what advertisers pay.
Eric Schmitt, VP Analyst in Gartner’s Marketing practice, said, “AI is not merely helping marketers execute campaigns faster. Advertising platforms are using it to exert greater influence over how marketers reach their audiences, what they pay, and the outcomes they achieve.”
According to Schmitt, the efficiency gains generated by AI at the platform level do not necessarily mean lower costs or better economics for advertisers. This makes independent evidence increasingly important for marketers seeking to assess whether their advertising investments are delivering the expected business returns.
Schmitt said, “AI was expected to make advertising more efficient, but improved platform economics does not necessarily translate into lower costs for the advertiser. CMOs need independent evidence that they’re getting the returns they expect.”
The shift is also changing the relationship between advertisers, agencies and media platforms. Advertisers and agencies are increasingly using platform interfaces and APIs to buy, manage and optimise media, giving advertising platforms a greater role in decisions that were traditionally shaped by marketers and agencies.
As AI becomes more deeply integrated into audience selection, ad delivery and pricing, Gartner recommends that CMOs take a more strategic approach to their platform portfolios.
First, marketers should prioritise the advertising platforms that are most strategically important to their businesses. Rather than spreading investment and management attention evenly across platforms, CMOs should concentrate resources, talent and oversight on those platforms that are critical to reaching priority audiences and delivering business outcomes.
Second, marketers should maintain a broader portfolio of additional platforms selectively. These platforms can help brands expand reach, test emerging opportunities and capture incremental performance without diluting focus from their most strategically important channels.
Gartner also recommends favouring platforms that provide greater transparency and support independent measurement. Such capabilities can allow marketers to make meaningful comparisons across platforms and independently evaluate whether reported performance translates into genuine business impact.
Schmitt said, “The more influence AI has over advertising decisions, the more important independent measurement becomes. CMOs need confidence that platform performance reflects real business impact, not just platform-reported results.”
For marketers, the issue is therefore moving beyond simply adopting AI-powered advertising tools. As platforms gain greater influence over media buying and optimisation, independent measurement and accountability are likely to become increasingly important components of advertising strategy.
The development could also reshape how CMOs evaluate media partners, with platform scale and automated performance increasingly needing to be weighed alongside transparency, measurement capabilities and the ability to demonstrate tangible business outcomes.
