August 17, Google implemented a global roll out that changed how budget-limited Smart Bidding campaigns using target CPA or target ROAS pursue the numbers advertisers set.
The rollout was completed August 27.
As a result, campaigns that had been beating those targets may move closer to them, which could leave advertisers paying more for results they were already getting for less.
Google says the change is designed to make performance more consistent when budgets change.
A target may have been set as an upper limit, while the campaign’s recent performance was well below it.
Under the new system, that target can have a greater influence on where performance settles.
What Google Changed in Target CPA and Target ROAS
The change affects how those campaigns respond to their bid targets when budgets are adjusted.
Google’s example is a campaign with a $10 target CPA that has been averaging $5. Its CPA may move closer to the $10 target under the new system.
Advertisers can lower the target, choose another figure, or switch bidding strategies. Google won’t change the target or daily budget for them.
Jessie Morris, director of paid media strategy at Intero Digital, says the target entered into Google should reflect what the business is willing to pay for a customer or lead, or the return it needs from its ad spend.
"The target in the platform should come from the economics outside the platform. If a $10 CPA is acceptable because the business can profit at $10, that's a real target.
"If it’s sitting at $10 because nobody revisited the setting after the campaign began producing $5 leads, the platform and the business are working from two different definitions of success."
How Should Marketers Set a Smart Bidding Target?
Google’s update gives its bidding system more influence over where campaign performance settles.
In Google Ads, advertisers set a target CPA or target ROAS for Smart Bidding.
Morris says those figures need to reflect what the business is willing to pay for a customer or lead, or the return it needs from its ad spend.
"Marketers need to separate a platform target from a business target. Google can manage bids against the number it receives, but it can't decide what a customer, a sale, or a qualified lead is worth to the company," she says.
"That decision still sits with the people managing the business."
Awareness and conversion account for 62.6% of total media spend, according to Gartner’s 2026 CMO Spend Survey.
The research and advisory firm also found that organizations with lower AI maturity can lean more heavily on short-term activity and channels that are easier to measure and automate.
A campaign can, therefore, hit its CPA target while bringing in fewer repeat customers, weaker leads, or sales with thinner margins.
"If a cheap lead never closes, or a sale comes with poor margin and low repeat value, the platform can report a win while the business records a weak result," Morris says.
What Should Marketers Measure After the Smart Bidding Update?
Fifty-five percent of organizations cite measurement and performance insights as the top AI capability they value when evaluating a marketing platform, according to Adobe’s 2026 State of Marketing in an AI-Driven World report.
That measurement needs to extend past the number Google is bidding toward.
Conversion volume, lead quality, revenue, margin, and customer value can show what a lower CPA or higher ROAS leaves out.
"Look at what happened to volume, revenue, lead quality, margin, and customer value after the change," Morris says.
She also cautions against reacting to a single reporting period.
"Judge the new results against the revenue, margin, customer value, or acquisition cost the campaign was expected to deliver."
If CPA increases after the update, conversion volume and lead quality can show what the business received in return.
A higher cost may be acceptable if the campaign produces more valuable customers. It may also leave the business paying more without gaining anything in return.
ROAS needs the same check. A higher return in the ad account can still come with lower margins or less valuable customers.
