Performance Drop after Enabling Consent Mode V2

Many advertisers are reporting severe performance drops in ROAS, Conversions, CPA and AdSpend after switching to Consent Mode v2. We at Fuel LAB found ourselves in the same situation, and we got confirmation from Google on the reason why.

When you switch your tags firing behavior to meet DMA requirements, also known as Consent Mode, depending on the type of implementation you have carried on, the signals arriving both to your Analytics and Advertising platforms will change dramatically.

While there are 2 ways to implement Consent Mode (Basic Implementation and Advanced Implementation) There are actually three scenarios to face, and most likely, you fall into scenario three.

De Facto, Consent Mode Basic was the standard of Consent Mode until the end of 2023, and users should have been already using it since a couple years, to meet European (but not only) privacy laws requirements.

Consent Mode Advanced, is a better and new way to ensure a less lossy data collection and processing, leveraging the AI within Google systems, to reconstruct conversion attribution and traffic data in a totally compliant way, even without cookies, nor user consent.

So, here are the three scenarios advertisings are facing, and the consequent resulting situations:

You are using Consent Mode Basic since years.No relevant changes, but you should start using Enhanced Conversions ASAP.
You have been using Consent Mode Basic, and you have moved to Consent Mode Advanced, with Enhanced Conversions tracking.You should expect an uptick in Conversion Rate by 5/10%.
You never used Consent Mode, and all of a sudden you have implemented Consent Mode Advanced or Basic.You are experiencing a severe drop in performance.
If you are experiencing a visibile drop in conversions and performance in your Google Ads campaigns, you will be very likely matching scenario three.

If you implemented Consent Mode, be it basic or advanced, switching from an unfiltered stream of data coming from your properties, your campaigns will be in a state of shock, and thus losing performance seriously, especially if you were relying on Smart Bidding strategies, such as Target ROAS (and also, but with less effect, Target CPA).

As you know, each campaign is associated with unique iterations of Google’s algorithms and AI processes. Each campaign, pretty much as each session you would make with ChatGPT, is unique and starts collecting data at campaign launch.

google ads performance drop with consent mode
Actual vertical drop in conversion from one of our client’s Google Ads account.

The modeling and performance optimization takes nominally a couple weeks to start working properly, and that’s because it evaluates every new piece of information with the historical data it collected. So, when all of a sudden data changes dramatically, the system is profoundly confused onto what’s going on. Virtually, it will ask itself questions like:

  • Am I doing it wrong?
  • Has the market changed completely?
  • Should I reduce the bid?

This is very similar to any disruptive and brusc change you’d do on a Google Ads campaign, with the difference that here we are impacting heavily not an environmental factor to the campaign (like budget, targets, and so on), but the very base of how the system works: high quality data streams.

While we were able to easily debug this with Google, Microsoft has not been neither as attentive, present, responsive, nor competent at addressing the issue. We have noticed the same performance drop in Bing Ads, with the usual Microsoft-style metric skewing. While Google will spend less when it loses confidence in the results it can bring with a Smart Bidding campaign, Bing will just start shooting to the stars its spend, while conversions flatline.

bing performance drop with consent mode
Severe conversion drop in Bing Advertising for the same customer, recovering after roughly two weeks.

Bing’s response to our enquiry, was to say that our tracking was not done correctly, claiming that the conversion can’t fire, or that the UET tag isn’t set properly. Of course, everything was set properly, exactly like it was before Consent Mode implementation, and was working flawlessly. Moreover, we have re-checked UET tag coverage and Conversion Tracking using Microsoft’s tools, and everything was reported to work normally.

In other words, as usual, Microsoft Support is terrible, and they have no clue on what’s going on, but, my assumption from experience is that the same situation as in Google is impacting your Bing Ads account, and the same solution applies to both cases.

I’ve been discussing this with our Google Partner accounts and the strategy we are going to follow is the current:

  • Firs of all, verify that your Consent Mode implementation is working Correctly
  • Secondly, make sure you have enabled Enhanced Conversions tracking
  • Then, take your target ROAS and target CPA’s down. You need to remove the bottleneck created, and allow the campaign to learn, adapt and optimize. Raising a bit your budgets would also be a good idea, to speed things up.
  • After two weeks, try lowering gradually your targets (be it ROAS or CPA, lower it be 10% bi-weekly).

This approach should gradually bring your campaigns to shine bright, and even brighter in time, as the machine learning models learn from the available observed and modeled data.

Bonus: Looker Studio lost opportunity meter report

If you have a lot of campaigns and a lot to go through, we have a free Looker Studio report that will be extremely useful to immediately identify those campaign losing a lot of share due to AdRank and bid-tied ranking.

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