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What is Incrementality?

Written by Lauri Potka | Jun 23, 2025 2:33:48 PM

Incrementality in marketing refers to the concept of quantifying the actual sales lift originating from investments to media, in contrast to sales driven by other factors, such as seasonality or promotions. Using causal inference methods, incrementality-based measurement provides marketers an estimate how much additional revenue each channel and campaign have been driving.

Visualizing Incrementality

The most common way to visualize incrementality is the sales decomposition chart that is often used in Marketing Mix Modeling (MMM). Below is an example of a sales decomposition chart for an eCommerce business on the Sellforte platform, where

  • Dark gray represents base sales (sales you would get without media or promotions),
  • Light gray represent promotion-driven sales
  • Colors represent sales driven by advertising on different platforms.

Why has Incrementality Become Popular?

While the concept of incrementality has been around for decades, it became popular in the 2020s as a counter-force to attribution-based media measurement.

Advertising platforms' own attribution methods typically overestimate campaign effectiveness, because they are unable to distinguish between

  • Conversions that would have happened without media,
  • Conversions that were truly incremental, driven by advertising on the platform, and
  • Conversions driven by other advertising platforms.

Similarly, cross-channel attribution, like Last-Click attribution, suffers from inability to measure the true incremental sales lift of different media, typically penalizing top-of-funnel channels, like Paid Social, and over-crediting bottom-of-funnel channels, such as branded search. Last-Click's challenges have been widely reported in comparison reviews to incrementality-based measurement, see for example The 3 Danger Zone of Last-Click or How to measure Meta correctly? GA4 Last-Click vs. MMM.

Why Does Incrementality Matter for Advertisers?

By starting to measure the true incremental sales driven by each channel and campaign, advertisers can asses the true ROI of their channels and campaigns, which enables advertisers to re-allocate their spend to most effective channels and campaigns.

Based on Sellforte research, transitioning from attribution-based measurement to incrementality-based measurement helps eCommerce business drive +6.5% more revenue. Most of the improvement is in campaign-optimization, as shown by the image below:

How is Incrementality Measured?

Incrementality can be measured using methods that estimate the causal relationship between marketing activities and sales of the company. The two of the most common methods include:

  • Marketing Mix Modeling (MMM): Statistical time-series methods for estimating relationship between media and sales.
  • Incrementality experiments (Incrementality tests): Controlled experiments to compare groups who are exposed to advertising vs. groups who are not exposed to advertising.

In practice, modern media measurement solution, such as as Sellforte, combine several methods high quality incrementality measurement, including MMM and incrementality tests. For a real-world example of modern media measurement, you can visit the no-sign-up Sellforte demo.

Case example: Brand Alley Started Incrementality-based Measurement with MMM and Conversion Lift Test

In a Sellforte case study, Brand Alley, a UK-based online fashion eCommerce, transitioned to incrementality-based measurement, leveraging both MMM and experiments.

Brand Alley first deployed Sellforte's MMM, to measure the true incremental sales impact of their channels. Brand Alley then started incorporating experiments, first focusing on Meta Ads using Meta's Conversion Lift test. Read the full case study here.