Digital advertising platforms have made it easier to track conversions across search, social, programmatic and connected TV. But a new 21-month study from Perfogro Ltd suggests that the settings used to assign those conversions can materially change how advertisers perceive channel performance — and where they decide to spend their next dollar.
Perfogro Ltd has published the results of a 21-month analysis examining how attribution window settings affect advertising performance reporting, drawing on more than 200 advertiser accounts, 1.4 billion ad views and 4.1 million recorded conversions between July 2024 and March 2026.
The study compared performance figures reported by advertising platforms with conversion and revenue data verified through advertisers’ customer relationship management (CRM) systems. The analysis covered paid search, paid social, programmatic display, native advertising and performance partnerships.
Its central finding is straightforward: there was no single attribution-window configuration in the dataset that matched verified CRM conversion results with an error margin below 11%.
That finding matters because attribution windows are not merely reporting preferences. They can influence automated bidding, campaign optimization and ultimately how budgets are distributed between media channels.
Google Ads, for example, distinguishes between attribution models and conversion windows. Its documentation notes that the selected attribution model can affect the conversions reported to bidding systems, including automated strategies such as Target CPA and Target ROAS.
In other words, measurement settings can become part of the media-buying mechanism itself.
View-through attribution emerges as a major source of uncertainty
Perfogro’s analysis places particular emphasis on view-through attribution, especially for display and connected TV (CTV).
When the researchers disabled a one-day view-through attribution setting and compared the resulting numbers against CRM records, they found that 67% of view-attributed conversions did not have a statistically meaningful exposure relationship. According to the study, those customers had converted through another, unrelated touchpoint during the same attribution window.
The distinction is important for advertisers evaluating channels where impressions are abundant but clicks are relatively scarce.
CTV illustrates the challenge. Perfogro reports that CTV return on ad spend (ROAS) was inflated between 31% and 180%, depending on campaign configuration, with an average inflation of 67% across the dataset.
That does not necessarily mean that CTV advertising is ineffective. Rather, it highlights the difficulty of determining whether an impression actually contributed to a conversion when the measurement framework gives substantial credit to exposure without a click.
The broader industry is wrestling with the same problem. The Interactive Advertising Bureau (IAB) has described fragmented standards and inconsistent signal quality as persistent obstacles to CTV measurement. Its 2025 standardized measurement guide was created specifically to address inconsistencies around impressions, reach, frequency and outcomes.
The stakes are increasing as CTV investment expands. IAB reported that CTV advertising grew 16% year over year in 2024, while digital video was expected to account for nearly 60% of U.S. TV and video ad spending in 2025.
Cross-channel attribution can make the problem worse
Attribution becomes even harder when multiple platforms use different definitions of a conversion window.
Perfogro found that 87% of the accounts examined during standard performance audits had different attribution-window settings across their active advertising platforms. Among advertisers simultaneously running paid search and paid social campaigns, double-counted conversions represented an average of 18.3% of reported conversions.
After the researchers normalized attribution windows across channels, blended ROAS fell by an average of 21.6% compared with unadjusted platform reporting.
The implication for advertisers is significant. Comparing the ROAS reported by Google, Meta, a DSP and a programmatic platform side by side does not necessarily produce a consistent view of incremental business impact. Each platform may be evaluating the same customer journey through a different measurement lens.
Google itself notes that lookback windows determine how far back an advertising interaction can receive attribution credit, while conversion windows determine the period after an interaction during which a conversion can be recorded.
That distinction can easily become buried inside campaign-management workflows.
Attribution can influence budget allocation
Perfogro argues that the financial consequences extend beyond dashboards.
In 61% of the accounts analyzed, the channel receiving the largest budget allocation at onboarding was also the channel using the most favorable default attribution window rather than the channel demonstrating the strongest verified downstream performance.
After attribution normalization and CRM reconciliation, 43% of accounts had at least one channel that was overallocated by more than 30% relative to its verified contribution.
The company estimates attribution-driven misallocation averaged more than £4,000 per account per quarter, while cumulative estimated misdirected spend across the study dataset reached approximately £8 million over the 21-month period.
Those figures should be treated as Perfogro’s estimates rather than an independently audited industry-wide measurement. Still, the underlying issue aligns with a broader shift in advertising measurement: marketers increasingly need to reconcile platform-level reporting with business outcomes rather than treating any single advertising dashboard as the definitive source of truth.
Gartner has similarly highlighted the growing complexity of proving advertising value and recommends combining attribution with testing rather than relying on a single measurement methodology.
What advertisers should do differently
For enterprise media teams, the lesson is not necessarily to abandon attribution windows or view-through measurement. Attribution remains essential for understanding customer journeys, particularly when users interact with multiple advertisements before converting.
The more practical response is to establish a consistent measurement framework across channels and reconcile platform reporting with CRM, transaction or revenue data.
That means documenting conversion windows, separating click-through and view-through contribution, standardizing definitions across DSPs and social platforms, and regularly testing reported performance against downstream business outcomes.
For CTV in particular, server-side integrations and stronger outcome measurement could become increasingly important. IAB has pointed to Conversion APIs as one way to connect ad exposure with business outcomes while supporting privacy-conscious data collaboration.
The bigger shift is from platform-reported performance to business-verified performance.
As programmatic advertising becomes more automated and AI-driven bidding systems make increasingly consequential decisions from conversion data, the quality of those conversion signals becomes an infrastructure issue rather than simply an analytics concern.
An attribution window can determine who gets credit. For advertisers, the more important question is whether that credit reflects who actually drove the business result.
Market Landscape
The advertising measurement market is moving toward greater cross-channel consistency as advertisers operate increasingly fragmented media portfolios.
Google’s data-driven attribution model distributes conversion credit based on historical interaction data, while other platforms use their own attribution frameworks and reporting conventions.
CTV presents an especially difficult measurement environment because advertisers must connect impression-level exposure with outcomes across fragmented streaming ecosystems. IAB’s recent measurement initiatives show that standardization remains an active industry priority.
For enterprise advertisers, this puts greater emphasis on independent measurement, CRM reconciliation, incrementality testing and, in some cases, marketing mix modeling. Gartner’s marketing measurement research similarly points toward combining attribution and testing to build stronger evidence of marketing impact.
The competitive landscape therefore extends beyond DSPs, ad exchanges and social advertising platforms. Measurement platforms, clean rooms, customer data platforms, conversion APIs and marketing analytics systems are increasingly becoming part of the same performance infrastructure.
Top Insights
- Perfogro’s 21-month study found attribution settings consistently diverged from CRM-verified conversion results, raising concerns for advertisers optimizing budgets across multiple channels.
- One-day view-through attribution produced particularly significant discrepancies, with Perfogro reporting weak exposure correlation for 67% of view-attributed conversions.
- CTV campaigns showed the widest reported ROAS inflation, reinforcing ongoing industry concerns about fragmented measurement and limited outcome signals.
- Cross-platform attribution differences contributed to double-counting, while normalized reporting reduced blended ROAS by an average of 21.6%.
- Enterprise advertisers may need CRM reconciliation, standardized attribution rules and incrementality testing alongside platform reporting to improve media allocation decisions.
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