For years, digital advertising has measured success through clicks, conversions and cost per acquisition. Google's latest measurement updates point toward a more difficult question: did the advertising actually create a result that would not have happened anyway?
Digital advertising has become extraordinarily good at counting things. Platforms can tell advertisers how many impressions an advertisement generated, how many people clicked, how many conversions followed and how much each action cost. Performance marketers have built entire strategies around metrics such as CTR, CPC, CPA and ROAS because they provide something advertising historically struggled to deliver: measurable evidence of what happened after money was spent.
The problem is that measuring what happened is not necessarily the same as measuring what advertising caused.
A customer who clicks a Google advertisement and buys a product may have purchased it anyway. Someone who sees a video campaign before searching for a brand may have already intended to visit the website. A returning customer attributed to a paid campaign may simply have used the advertisement as a convenient route back to a company they already knew.
Traditional attribution can record all of these conversions. It cannot always tell advertisers how many of them were genuinely created by the advertising.
Two Google Ads updates announced this week put that distinction back at the center of performance measurement. As reported by Search Engine Land on October 7, Google is expanding Conversion Lift measurement to Search and Performance Max campaigns for eligible advertisers. A second update, reported on October 8, expands funnel reporting by incorporating video impressions into the conversion journey and giving advertisers a broader view of how users move from exposure to purchase.
Taken together, the updates reflect a larger shift in advertising measurement. The industry is moving beyond asking which campaign received credit for a conversion and toward asking whether that campaign actually created additional business.
Attribution tells you who gets the credit. Incrementality asks whether the result was created.
The difference between attribution and incrementality sounds technical, but commercially it is enormous.
Imagine that 1,000 people purchase a product after being exposed to an advertising campaign. A conventional attribution system might report 1,000 conversions and calculate campaign efficiency based on the amount spent to generate them. The campaign appears successful.
But suppose 700 of those customers would have purchased the product even without seeing the advertising. In that case, the campaign did not really create 1,000 additional sales. Its incremental contribution was closer to 300.
This is the problem Conversion Lift is designed to address. Rather than relying only on observed customer journeys, lift studies compare groups exposed to advertising with comparable groups that were not exposed. The difference in outcomes helps estimate how many conversions were actually caused by the campaign.
Google has offered forms of Conversion Lift measurement for some time, particularly across video and other campaign environments. Extending the capability to Search and Performance Max matters because these are areas where attribution can be particularly difficult to interpret.
Search advertising often captures users who already have significant intent. Someone searching for a company's exact brand name may be extremely likely to convert, regardless of whether a paid advertisement appears above the organic result. Performance Max creates a different challenge because Google's automation distributes advertising across multiple properties and formats, making it harder for advertisers to understand which interactions genuinely changed customer behavior. The same automation trend is behind Google moving Search campaigns to AI Max.
A campaign can therefore produce excellent attributed performance without necessarily producing an equally strong incremental effect.
The cheapest conversion may not be the most valuable conversion
This distinction has major implications for performance marketing.
For years, advertisers have optimized toward lower acquisition costs. If Source A produces conversions at €20 and Source B produces them at €35, the obvious decision is usually to allocate more budget to Source A.
Incrementality complicates that decision.
Source A may primarily reach existing customers or people who were already preparing to buy, while Source B may introduce the product to completely new customers who would never have converted otherwise. The €35 acquisition could therefore create more additional revenue than the €20 acquisition.
Neither CPA nor ROAS necessarily reveals that difference on its own.
The same applies to traffic. A source can deliver excellent click-through rates, cheap visits and impressive conversion numbers while contributing relatively little new demand. Another source may look less efficient in traditional attribution but play a much larger role in creating awareness, influencing consideration or introducing new customers.
This is one reason advertisers are becoming more interested in incrementality. As advertising platforms become increasingly automated, optimizing toward attributed conversions alone can encourage systems to find customers who are easiest to convert rather than customers whose behavior can actually be changed by advertising.
There is an important difference between finding demand and creating demand.
Both have value, but they should not automatically be measured in the same way.
Google is also changing how the funnel is represented
The second Google Ads update announced this week addresses another weakness in conventional performance measurement: not every valuable advertising interaction produces a click.
Google has expanded its funnel reporting to include video impressions, allowing advertisers to see how exposure to video advertising can contribute to a journey that later results in a conversion. Instead of presenting the customer path primarily through direct interactions, the reporting provides more visibility into earlier stages of the funnel.
This matters because consumer journeys rarely follow the neat sequence implied by many analytics dashboards. A person might see a video advertisement, encounter the brand again several days later, search for the product, visit the website through another channel and eventually purchase directly.
Which channel created the sale?
There is no simple answer. Search may have captured the final intent. Video may have introduced the brand. Another source may have provided the information that convinced the customer. Direct traffic may ultimately record the purchase.
Traditional last-click attribution compresses that entire journey into one interaction. More sophisticated attribution models distribute credit across multiple touchpoints, but even then they are still primarily deciding how existing credit should be allocated.
Incrementality asks a different question: what would have happened if one of those advertising exposures had never occurred?
That question is harder to answer, but it is much closer to what advertisers ultimately want to know.
Traffic volume and traffic value are moving further apart
For the traffic industry, Google's updates highlight a broader development. The value of traffic can no longer be understood simply through the number of visits it generates or even the number of conversions directly attributed to it.
A traffic source may deliver large volumes of users who already intended to purchase. Another may introduce completely new audiences but appear weaker when evaluated through short attribution windows. A third may influence future conversions without receiving direct credit at all.
This means metrics such as CPC, CTR and CPA remain useful, but they describe only part of the economic value of traffic.
CPC tells an advertiser how much a visit costs. CTR indicates how effectively an advertisement generates clicks. CPA measures the cost associated with an attributed conversion. None of these metrics independently answers whether the advertising changed customer behavior.
As measurement becomes more sophisticated, traffic buyers are likely to demand a broader picture. They will want to know not only whether traffic converts but what kind of customers it brings, where those customers are in the purchase journey and whether the traffic contributes incremental value. It is the same move from volume to quality we described in The End of Cheap Impressions?
This does not make traditional performance metrics obsolete. Advertisers still need to control costs and understand campaign efficiency. The shift is toward combining those metrics with a better understanding of causality.
This changes how traffic should be evaluated
For traffic marketplaces such as Traffberry, the distinction between attributed performance and incremental performance is particularly relevant.
A marketplace connects buyers with different types of traffic, and those sources should not necessarily be expected to perform identically. Some publishers may be strong at discovery. Others may deliver high-intent users. Certain traffic sources may perform exceptionally well for customer acquisition, while others may be more effective for retargeting or conversion.
If every source is judged only by immediate CPA, buyers risk undervaluing traffic that contributes earlier in the customer journey.
Better traffic evaluation therefore requires context. Buyers need to understand the source, audience, format, acquisition method and expected role of the traffic before deciding which performance metrics matter most. On the Traffberry marketplace every listing shows the traffic type, pricing model, volume and GEOs, and the ad networks directory compares formats and pricing models with a source for every fact.
A publisher introducing a brand to a new audience should not necessarily be evaluated using exactly the same framework as a source capturing users who are already searching for that brand. Both can generate valuable traffic, but they create value at different points in the funnel.
This is another reason transparency matters in traffic marketplaces. When buyers understand what they are purchasing, they can evaluate it against the correct objective instead of expecting every source to produce the same type of conversion.
The next performance metric is not another click metric
Google's latest updates do not eliminate the measurement problems of digital advertising. Lift studies require sufficient data, experimental design has limitations, and no platform can provide a perfect view of every interaction influencing a consumer's decision. Advertisers should also be cautious when relying entirely on measurement systems operated by the same platforms selling the advertising being measured.
Nevertheless, the direction is important.
Digital advertising spent much of the last two decades proving that it could measure user behavior more precisely than traditional media. The next challenge is proving that the behavior advertisers observe was actually changed by the advertising they purchased.
That distinction becomes even more important as AI takes over more campaign optimization. An automated system instructed to minimize CPA will become extremely efficient at finding cheap attributed conversions, a risk we covered in AI Is Buying Traffic Faster Than Humans. If the real business objective is acquiring customers who would not otherwise have converted, the optimization target needs to become more sophisticated.
For advertisers, this means asking harder questions about performance. For publishers and traffic providers, it means demonstrating value beyond raw volume. For marketplaces, it means giving buyers enough information to understand what kind of traffic they are purchasing and what role it can realistically play.
The future of performance advertising will still involve clicks, conversions and acquisition costs. They are not disappearing. But they are increasingly becoming inputs rather than the final answer.
Because the most important question in advertising is not how many conversions appeared in the dashboard.
It is how many of those conversions would never have happened without the advertising.
Sources and further reading
- Search Engine Land: Google opens Conversion Lift to Search and Performance Max (October 7, 2026)
- Search Engine Land: Google Ads adds video impressions and funnel reporting to Overview page (October 8, 2026)
- Google Ads official website