A search practitioner’s guide to measurement in a cookieless world.
Why should I care?
So unless you’ve been living under a rock for the last couple of years, you’ll likely have heard about the ongoing discussions around third-party cookies and their impact on digital advertising. While last year’s developments have shifted the timeline for their full deprecation in Chrome, we still operate within an environment where cookie degradation is all too pertinent, and the need for robust and privacy-centric measurement solutions remains as critical as ever. If this is still relatively new to you, then I’d encourage you to pause here and review our previous blogs for foundational context.
Right, now we’re up to speed…
Demand-led Environment
As search marketers, we’ve so far been relatively insulated from any meaningful disruption that cookie degradation has posed to our advertising practices. Comforted by the blanket of ‘bottom-of the funnel’ keyword-based targeting (unlike our display and programmatic counterparts), and discounting recent shifts towards AI-based campaign types (PMax), the fundamental mechanics of how search advertising works is still the same as it has ever been: user searches > search query matches to keyword > relevant ad is served > user clicks ad.
We still operate in a uniquely demand-led environment, so to-date, there has been no tangible risk presented by any third party cookie-blocking innovation that has forced us to massively change the way in which we do things.
One obvious caveat here would be the practicalities of implementing anything beyond a very basic audience strategy, where we do now have limitations on the addressable audiences we are able to effectively reach and target - but the use of Customer Match and GA4 audiences (more on this later) go a fair way towards mitigating this risk. And again, the equivalent impact here is much less felt in the world of search, relative to channels further up the funnel.
While the timeline for third-party cookie deprecation in Chrome has shifted, the limitations on audience strategies and the increasing importance of first-party data remain significant factors to consider in search marketing.
We are already in a cookieless world… sort of…
So, whilst the process of reaching our target audience in search remains relatively resilient, the challenges in accurately measuring user behavior once they reach our site are not new. As this section highlights, the world of search has, in fact, been operating in a 'cookie-limited' environment for some time due to developments like Apple's ITP. This underscores the importance of adopting measurement solutions that are not solely reliant on third-party cookies, ensuring we are prepared for the continued evolution of privacy restrictions.
Apple introduced the first iteration of its ITP technology way back in 2017, paving the way for subsequent releases over the years, further restricting the use of both third and first-party cookies across websites. With a current c.20% browser market share globally, this represents a not-insignificant volume of potential search traffic that comes with so-called ‘cookie-tax’ (i.e. significant limitations of 1st & 3rd party cookie setting and thus a higher proportion of conversions occurring that we are not able to directly measure).
Yet despite this, we are still able to confidently measure and report on conversions that matter to us. We are still able to optimise directly towards meaningful on and off-site actions, rather than click-based KPIs. Collectively, advertisers are still placing faith in Google’s platforms as evidenced by a 10% increase in year-on-year Google Search ad spend. Importantly, what we didn’t see was a sudden drop-off in the number of conversions being recorded through the paid search channel.
Conversion data is modeled
So how can this be? Well, a number of ‘cat-and-mouse’ driven solutions released by Google over recent years has helped to maintain the status quo in the underlying numbers that we’re able to see in our reporting & optimization platforms.
Firstly, most online conversion data (captured from your website’s conversion tags via Google Ads conversion tracking, Google Analytics or Floodlight) reported on in-platform is already being modeled. That is, the numbers upon which we base all of our paid search budgeting, target-setting and KPI-optimisation are actually a blend of directly measured and estimated volumes and values. And to this end, Google has already succeeded greatly in overcoming what could have presented a significant challenge: maintaining trust and faith in the data being used to make decisions.
Introducing this modeled data as an ‘embedded-AI’ driven technology, rather than an advertiser-driven choice through ‘opt-in/out’ capability, has conveniently and unsurprisingly resulted in 100% adoption of modeled data. There is little discourse centered around modeled vs. unmodeled conversions; they are one and the same. And whilst it is technically possible to leverage SA360 floodlight event reports to deduce the relative proportion of modeled vs. unmodeled data - there is no real actionable purpose to this exercise, beyond observing & noting the difference, or troubleshooting wider technical measurement challenges.
This reliance on modeled data is only likely to increase further as the industry moves towards more privacy-preserving measurement methods, further reinforcing its importance for accurate reporting and optimization.
Our tags have also changed
Beyond conversion modeling then, we have also seen a shift in recent years of Google’s approach to sitewide-tagging to further mitigate the impact of existing cookie-blocking measures. The roll-out of the Google Tag or gTag (formerly Global site tag) as the single source of truth concerning online measurement across both Google Ads & SA360/Floodlight, has allowed for on site conversion tracking to operate according to first-party, rather than third-party cookie restrictions. Whilst still restricted in certain environments (Apple…), the use of GTag for conversion measurement paves the way for a whole host of technologies and implementations (see below) that will be imperative for the continuing preservation of conversion measurement. As a result, the Google tag can be considered the single most important piece of any durable and privacy-centric measurement foundation.
So what’s around the corner and what do I need to do?
While the timeline for changes in Chrome has evolved, it's essential for search marketers to proactively adopt best practices to ensure accurate measurement and prepare for the ongoing shift towards a more privacy-centric digital ecosystem. The following actions will help preserve and enhance your measurement capabilities, setting you up for long-term success.
Much of this is already covered in our previous blog post “What The Cancellation of Cookie Deprecation REALLY Means”, but it may not be obvious which implementations are most relevant and necessary for search activation specifically. As such, we’d recommend you pay particular attention to the following action points to ensure that your search measurement is appropriately future-proofed:
- First and foremost, we will already assume that the first foundational component of durable measurement is in place: the aforementioned Google Tag. Not only will this help to maintain an accurate record of directly-measured conversion events on-site, but it will also provide the framework of enablement upon which most of the following solutions are required to work (i.e. the Privacy Sandbox).
- Sticking with tagging infrastructure, we would strongly recommend exploring the implementation of server-side tagging (sGTM). Not only does this provide a more durable and robust foundation for capturing user data in a privacy-centric and first-party environment, but it also opens the door to a wide variety of solutions centered around value-bidding in search. Data can also be controlled and manipulated in real-time at the point of capture, ahead of its ‘pushing’ back out to the relevant measurement tags (Floodlight/Google Ads). An example use-case here would be real-time profit bidding in Google Ads/SA360 via Soteria, which is made possible through the implementation of sGTM.
- As an alternative to sGTM, it may also be worth exploring Google Tag Manager's recent launch of First-Party Mode. This is a configuration that prioritizes setting first-party cookies via client-side JavaScript instead of relying solely on HTTP responses, which is increasingly important for enhancing the longevity and reliability of website tracking (analytics, conversions) in privacy-focused browser environments. Where First Part Mode differs from sGTM is in its focus on optimizing client-side cookie behavior rather than moving the entire tagging process server-side, allowing for more resilient first-party data collection without the full infrastructure shift of sGTM.
- Next on your list - particularly if you are operating within the UK or the EEA (where it is a legal requirement!) should be the adoption of Consent Mode. This dictates the way in which your Google tag (working across Google Ads, Analytics and SA360 Floodlight) behaves based on the differing consent preferences of your website’s users. Not only is this a key solution for maintaining regulatory compliance, but this also holds a key tangible benefit to your search data: Remember that modeled conversion data we were talking about earlier? Well, consent mode applies its own conversion modeling in situations where consent was not explicitly provided by the user & thus would normally present a measurement gap.
- An equally important implementation to Consent Mode is that of Enhanced Conversions and/or Enhanced Conversions for Leads. Underpinned by first-party data and compatible with both Google Ads and SA360, this technology bridges measurement gaps where a lack of cookies would otherwise result in a conversion blind-spot. Hashed first party data (such as an email address or phone number) is captured at the point of conversion, and used to match the user back to Google’s own sign-in data to join the dots between the click and the conversion.
- Next, we should be looking to integrate GA4 data as much as possible within our activation platforms - that is for both Google Ads and SA360. Not only is this largely a necessity for most advertisers migrating away from Google Analytics UA, but this also presents better & more durable opportunities concerning audiences and engagement. GA4 audience imports should be prioritized for search accounts, given their session-based composition, and GA4 events themselves should be tracked as a key measurement source of truth.
- And finally, we can’t mention audiences without noting the importance of Customer Match. Not only should a shift towards GA4 audiences be prioritized, but the importance of first-party audience collection continues to become even more critical as cookie-based audiences are phased out. Consequently, a customer match-first audience framework is a critical tool that any paid search strategy aiming for success must incorporate in order to future-proof and enhance its search audience strategies.
In conclusion, while the immediate landscape of third-party cookies in Chrome has shifted, the core principles of effective conversion measurement in search advertising remain unchanged. Embracing privacy-centric solutions like the Google Tag, Consent Mode, Enhanced Conversions, GA4 integration, Customer Match, First Party Mode, and exploring server-side tagging is not simply about reacting to change; it's about proactively building a durable and successful measurement strategy for the evolving digital future. Staying informed and adapting to these changes will be critical for search marketers to maintain a competitive edge and ensure accurate, privacy-compliant campaign optimisation.
Thankfully however, here at Incubeta we have a strong track record of supporting our clients through their measurement and privacy journeys, and we’re here to help…