By August, most marketing teams have shifted into festive planning mode. Media plans are being signed off, audience segments have been finalised, creative assets are entering production, and budgets have largely been committed. Conversations naturally revolve around execution: which channels deserve more investment, which offers should be promoted, and how campaigns should be sequenced across the festive calendar.
What receives far less attention is how those campaigns will actually be measured. Weeks before the festive season are often the only opportunity to strengthen the foundations of performance marketing before campaigns go live. Once September arrives, optimisation decisions are driven by the data already being collected. If the measurement framework isn't capable of separating genuine advertising impact from seasonal consumer behaviour, every decision that follows is built on an incomplete picture.
This is especially true for retargeting.
For many brands, festive campaigns represent the single largest investment in re-engaging existing users. Consumers naturally return to shopping apps, revisit abandoned carts and compare products more actively during this period, making retargeting one of the most effective ways to convert existing intent into measurable business outcomes.
The challenge is that these same behavioral shifts also make campaign performance harder to evaluate.
The festive season is unlike any other period in the marketing calendar because consumer intent rises independently of advertising.
People are already planning purchases. They are actively searching for offers, comparing brands and revisiting products they considered weeks earlier. As a result, conversion rates tend to improve across almost every campaign.
This creates a common measurement trap.
When users are already more likely to convert, attribution platforms naturally report stronger campaign performance. A retargeting campaign that reaches a customer shortly before purchase may receive full credit for the conversion, even if that customer was already planning to return.
That does not mean attribution is flawed. Attribution answers an important question: which marketing touchpoint received credit for a conversion?
However, festive marketers need to answer a second question as well.
Did the advertising actually change customer behaviour, or did it simply capture demand that already existed?
That is the role of incremental lift.
Incremental lift measures the additional conversions generated because advertising was shown, rather than the conversions that would have occurred naturally. During high-intent periods such as the festive season, this distinction becomes critical because it reveals the true business impact of media investment—not just the conversions attributed to it.
💡What is incremental lift?
Incremental lift measures the additional outcomes created by advertising by comparing users who were exposed to a campaign with a comparable group that was not. It helps determine whether advertising genuinely influenced behaviour instead of simply receiving attribution for an existing purchase journey.
💡Why is incremental lift important during festive campaigns?
Festive periods naturally generate higher consumer intent. Many users return to apps or complete purchases regardless of advertising. Incrementality helps marketers distinguish between conversions driven by seasonal demand and conversions directly influenced by marketing.
💡Is attribution the same as incrementality?
No. Attribution identifies which touchpoint received credit for a conversion. Incrementality measures whether advertising changed the outcome in the first place. Both are valuable, but they answer different business questions.
💡Can retargeting and incrementality work together?
Yes, retargeting identifies high-intent users, and incrementality tells you whether reaching them with an ad actually changed the outcome
Retargeting and incrementality are often treated as separate capabilities. One is viewed as a media strategy, the other as a measurement exercise.
In reality, they are most valuable when they work together.
Retargeting is designed to reconnect with users who have already demonstrated intent. Incrementality determines whether those campaigns are actually influencing their decisions. Combining the two allows marketers to move beyond reporting conversions and towards understanding which campaigns, audiences and creative strategies are generating genuinely incremental business outcomes.
This shift changes how optimisation happens during the festive season.
Instead of increasing investment simply because attributed ROAS looks strong, marketers can identify where advertising is producing measurable behavioural change. Budgets can then be redirected towards audiences that demonstrate genuine incremental lift, while reducing spend on users who were already likely to convert organically.
In other words, incrementality transforms retargeting from a campaign tactic into a continuously improving performance strategy.
Although incrementality relies on statistical modelling, the underlying process is straightforward.
Establish test and control groups before campaigns launch. Randomly divide eligible audiences into statistically comparable groups so that one receives advertising while the other does not; typically a 90:10 split, so the large majority of the audience still sees the campaign while a small, statistically valid slice is held back as a clean comparison group.
Define business outcomes, not just media metrics. Installs are only one indicator of success. Registrations, purchases, repeat transactions, and revenue quality often provide a more meaningful view of campaign performance.
Compare exposed and unexposed audiences. The difference in performance between the two groups represents the incremental impact of advertising rather than seasonal demand alone. Intent to Treat, PSA, and ghost bidding are three established methodologies that strengthen the validity of this comparison. Ghost bidding in particular- placing a bid for control-group users without ever serving them the ad- lets their natural journey be tracked at no added media cost, which makes continuous testing easier to sustain across a nine-week festive window.
Optimise continuously throughout the festive season. Incrementality should not be treated as an end-of-campaign report. As audience behaviour changes across the festive calendar, lift insights should continuously inform budget allocation, audience strategy and creative optimisation.
Every festive season produces stronger marketing reports. Conversion rates improve, retargeting campaigns appear more efficient, and return on ad spend trends upward as consumers naturally become more active. Those outcomes are real, but they don't always tell the complete story.
For marketers, the more valuable question isn't how many conversions a campaign generated; it's how many it genuinely influenced. That distinction is becoming increasingly important as festive budgets grow and customer journeys span multiple channels, devices and moments of engagement. Retargeting and incrementality, used together, are what make that distinction measurable rather than theoretical.
As performance marketing evolves, measurement can no longer be viewed as an exercise in reporting results after the fact. It has become an essential part of improving them. The marketers who outperform this festive season will not necessarily be those with the largest budgets or the highest attributed ROAS, but those who build a continuous feedback loop between activation and measurement, using evidence to refine every optimisation decision along the way.
Ultimately, the goal of festive marketing isn't simply to reach more users. It's to understand where marketing genuinely changed behaviour, and to use those insights to make every subsequent campaign more effective than the last.
Turn festive retargeting into a performance strategy. With mDSP, brands go beyond attribution to capture incremental impact across CTV and mobile. Connect with us: https://mdsp.co/contact