Explained: Measuring Incrementality

Incrementality experiments are a vital component of any robust measurement strategy. These tests help isolate the true effect of advertising by comparing performance across markets, DMAs, audiences, and stores with varying levels of media exposure. By accounting for natural upgrade patterns and external influences, incrementality experiments provide a real-world perspective on incremental lift, making them especially effective in measuring marketing.

It’s crucial to ensure that the test and controls selected for testing are well-matched, so the effects observed in the test and control groups are reasonably similar. This careful matching is an often overlooked but critical part of the process that enhances the reliability of results, decisions and actionable insights.

Incrementality methods, such as geo-tests, holdouts, go-dark tests, spend shifts, and channel comparisons, offer flexible ways to understand media impact across channels and investment levels. Together, these approaches form an essential foundation for any measurement plan, enabling marketers to distinguish true business impact from activity that would have occurred naturally.

Holdout Tests

Holdout tests exclude a segment of your audience from a campaign to create a control group. By comparing outcomes between exposed and unexposed groups, you can accurately measure the incremental impact of your marketing efforts. This approach is essential for evaluating the true effect of different offers, creatives, and channels on specific audiences, helping to optimize CRM and prospecting campaigns.

Go Dark Tests

Go dark tests temporarily remove a channel from select markets to create a clear contrast with markets that continue receiving ads. This approach is especially useful for emerging or smaller channels where the signal from normal activity may be too subtle to measure. By pulling spending entirely, the effect of that channel becomes more visible.

Spend Shift Tests

Spend shift tests raise investment in some markets while reducing it in others. This helps determine how changes in spending affect upgrade behavior and whether additional dollars generate proportional incremental lift. These tests work best for high volume channels where spending decisions have meaningful financial impact.

Cross Channel Interaction Tests

Cross channel interaction tests evaluate how channels influence each other when used in different combinations. By emphasizing one channel in a group of markets and another channel elsewhere, teams can see whether certain pairings improve overall performance or reduce the need for spend in other parts of the mix.

Channel Comparison Tests

Channel comparison tests assign two channels to different sets of markets to identify which one drives stronger incremental response. This method is helpful when choosing between channels that serve similar objectives or reach overlapping audiences.

Switchback Tests

Switchback tests alternate media exposure within the same market during a defined period. This design works well when precise geographic targeting is not possible. Because the same market experiences both treatment and non-treatment phases, the results reflect differences relative to the market’s own baseline.

Incrementality measurement cuts through the ambiguity that plagues traditional attribution. By using methods such as holdouts, go-dark tests, spend shifts, and geo-based experiments, marketers can separate true lift from behavior that would have occurred naturally. These tests provide clarity on which channels drive growth, how much incremental value additional spend delivers, and how different parts of the media mix interact with one another.

Bridgetree helps organizations operationalize incrementality at scale. We design experiments that align with business goals, ensure test and control groups are properly matched, and integrate results into broader measurement frameworks alongside MTA and MMM. The outcome is not just better testing, it’s a repeatable system for smarter investment decisions, reduced waste, and sustained performance in an increasingly complex marketing ecosystem.