>What matters is incremental ROAS - not the conversions following exposure, but rather the conversions that would not have happened but for the exposure. [...] there's no untouched part of the market that's never seen a Coke ad against which you can do an A/B test.
Sophisticated advertisers like Coca-Cola are aware of the concept about incremental ROAS. They can't do the exact A/B test scenario of isolated consumers you're talking about but decades ago, they did do A/B tests in different tv markets where one city had more ads than another and the city with more ads had higher sales. (What the industry jargon calls "lift" from advertising exposure.)
So even brands that are already very well-known by most of the public still constantly do A/B tests to measure incremental conversions in all media including digital, magazines, sports sponsorships, etc. Back in the late 1990s, many advertisers noticed that running banner ads on Yahoo didn't work which contributed to their stock price crashing. Recently, a lot of advertisers (e.g. Proctor & Gamble) quit spending ad dollars on 2nd and 3rd-tier ad exchanges because their A/B measurements showed they were a waste of money. (The "1st-tier" ad exchange examples would be Google & Facebook.)
> Recently, a lot of advertisers (e.g. Proctor & Gamble) quit spending ad dollars on 2nd and 3rd-tier ad exchanges because their A/B measurements showed they were a waste of money.
Can you share a link? I work in digital marketing and would be super interested in more info on this.
Sophisticated advertisers like Coca-Cola are aware of the concept about incremental ROAS. They can't do the exact A/B test scenario of isolated consumers you're talking about but decades ago, they did do A/B tests in different tv markets where one city had more ads than another and the city with more ads had higher sales. (What the industry jargon calls "lift" from advertising exposure.)
So even brands that are already very well-known by most of the public still constantly do A/B tests to measure incremental conversions in all media including digital, magazines, sports sponsorships, etc. Back in the late 1990s, many advertisers noticed that running banner ads on Yahoo didn't work which contributed to their stock price crashing. Recently, a lot of advertisers (e.g. Proctor & Gamble) quit spending ad dollars on 2nd and 3rd-tier ad exchanges because their A/B measurements showed they were a waste of money. (The "1st-tier" ad exchange examples would be Google & Facebook.)