IAB Tech Lab releases results of Privacy Sandbox gap analysis

Posted on Tuesday 06 February 2024 | IAB UK

Ahead of the planned deprecation of third-party cookies on Chrome in H2 2024, IAB Tech Lab has carried out an in-depth gap analysis of Privacy Sandbox, which is developing privacy-focused tools for advertisers to target and measure campaigns post-cookies

Update, Thursday 15 February: Chrome has issued a response to IAB Tech Lab’s gap analysis of Privacy Sandbox (detailed below). It states that Chrome “appreciates the IAB Tech Lab's mission to educate its members on new technologies that will impact the digital ecosystem, and looks forward to continuing to work together to support a deeper understanding of Privacy Sandbox.” However, it also outlines key areas where it believes “the analysis contains many misunderstandings and inaccuracies, which we consider important to correct in order to provide accurate information to the ecosystem.” You can read the details in the full response here

Chrome concludes: “We continue to move forward with our plans to phase out third-party cookies in H2 2024, subject to addressing any remaining competition concerns from the UK Competition and Markets Authority. We're encouraged by the many IAB members actively building solutions using the Privacy Sandbox APIs. We welcome continued collaboration with the IAB Tech Lab, and support their call to action for companies to start testing the Privacy Sandbox APIs and share feedback on how the Privacy Sandbox technologies can be improved now and in the future.”


There’s little debate that The Privacy Sandbox APIs are poised to usher in a transformative era in digital advertising fundamentals. However, while they aim to address privacy concerns, they also introduce noteworthy challenges. IAB Tech Lab’s Privacy Sandbox Taskforce has conducted a gap analysis exploring the implications of the removal of third-party cookies. The process has taken six months and involved over 65 companies the assess the functionality and implications of Privacy Sandbox.  

This work has identified several crucial functions within Sandbox - including frequency capping, video advertising, audience creation, and impression counting - that either lack support or face limitations. IAB Tech Lab is also now inviting industry stakeholders to participate in a 45-day period for public comment on the analysis, which will remain open until 22 March 2024. Find the full analysis and how to contribute here.  

Anthony Katsur, CEO of IAB Tech Lab, said: "Embracing Google's Privacy Sandbox is a seismic shift in the advertising landscape, departing from the industry's trajectory over the past 25 years. Our findings highlight that the industry isn't ready yet and identify multiple challenges to implementation due to limitations in accomplishing key advertising objectives. Chrome is focused on providing discrete components that support aspects of use cases, but which ultimately cannot be assembled into a whole that provides a viable business foundation." 

Speaking for IAB UK, Tim Elkington, Chief Industry Officer, highlighted the need for a collaborative response to resolve the challenges identified: “At IAB UK, we’ll be continuing to work closely with Google and our wider membership base to facilitate solutions to the issues that Tech Lab has raised. Knowing where more work is needed is essential in allowing the industry to proactively focus efforts and develop functional alternatives for targeting and measuring ads.  

“Google has been clear that it is not trying to replicate third-party cookies and we know that the deprecation of cookies is going to result in a more fragmented digital ecosystem. That is why it’s so important to ensure that you are involved in this work, thoroughly testing the products available and feeding back to developers. It’s in all of our interests to identify and address where more work is needed so we can make this transition as smooth as possible.”  

Key findings from Tech Lab’s gap analysis include... 

Audience Management 

Summary: The landscape of audience management in digital marketing is marked by a blend of supported functionalities and notable challenges. While some aspects like targeting across multi-domain publishers and targeting pre-existing audiences are achievable, significant gaps remain. Key areas such as exclusion targeting, look-alike modelling, and interest group management for competing entities are either impractical or unsupported, underscoring the need for continued innovation and adaptation in digital advertising strategies. The reliance on technical and contractual nuances further highlights the complexity of navigating audience management effectively in the proposed digital ecosystem. 

Auction Dynamics 

Summary: The auction dynamics in digital advertising are marked by a mix of supported, degraded, and unsupported functionalities. Challenges like avoiding self-competition in bidding, implementing effective frequency capping, and managing budget pacing reflect the complexities and limitations of the current systems. While deal ID utilization is supported, the lack of competitive separation and inadequate tracking of “no bid” responses highlight areas needing improvement. 

Creative & Rendering 

Summary: The ‘Creative & Rendering’ segment of digital advertising is facing a period of significant adaptation due to evolving technologies and privacy considerations. While quality assurance and malware protection for creatives remain robust, the industry is grappling with the challenges of transitioning to new formats and standards, especially in video advertising. The shift from traditional methods to the fenced frame model and the limitations in supporting various ad formats present hurdles that require innovation and collaboration across the digital advertising ecosystem. 


Summary: The reporting functions in digital advertising are experiencing a period of transition and challenge, primarily due to new privacy-focused technologies and standards. While some functionalities like bid price reporting for winners and host domain reporting remain robust, the industry faces significant limitations in areas like bid loss reporting, revenue accrual validation, and detailed attribution reports. These changes reflect a shift towards privacy preservation but also highlight the loss of critical business functionality. 

Technology & Interoperability 

Summary: The digital advertising ecosystem is navigating a complex transition with the Privacy Sandbox’s introduction, impacting how ads are served, managed, and reported. While the opt-out of the Privacy Sandbox offers a temporary solution, it leads to a degradation in ad serving capabilities and interoperability. Challenges in managing invalid traffic, ad serving latency, cost efficiency, data security, algorithm integrity, and maintaining brand safety and fraud protection underpin the need for evolving discussions around core functionality unavailable. 

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