Introducing Sellforte Incrementality Testing & Incremental Attribution

For ecommerce and DTC brands, paid media is often one of the biggest and most closely managed growth investments. Performance teams are constantly deciding how much to spend across Google, Meta, TikTok, and other channels, which campaigns to scale, and where to pull back.

The problem is that the numbers they use to make those decisions rarely agree. Google has its view. Meta has its view. TikTok has its view. And GA4 often tells a different story again.

Yet none of those attribution systems necessarily tell you what your marketing actually caused. A platform can take credit for sales that would have happened anyway because of existing demand, repeat customers, or other marketing activity. At the same time, another channel can play an important role in creating demand but receive very little credit because the customer converts somewhere else.

For ecommerce and DTC performance teams, that creates a fundamental measurement problem: which parts of your paid media are actually generating incremental sales, and which are simply getting credit for revenue that was already going to happen?

Until now, getting an independent answer has often meant making the jump into a full Marketing Mix Modeling program. For many ecommerce and DTC brands with established paid media programs, that can be a big first step when the immediate need is much simpler.

Today, we’re introducing two new Sellforte packages designed specifically for that starting point: Incrementality Testing and Incremental Attribution.

Incrementality Testing gives marketers a standalone way to prove whether specific marketing activity genuinely drove additional sales. Incremental Attribution builds on that foundation, turning incrementality into an always-on view of performance across platforms, campaigns, and ad sets.

The idea is simple: prove what’s incremental, then measure it continuously.

Attribution tells you who gets credit, Incrementality tells you what actually changed

Most ecommerce performance teams already have plenty of attribution. The harder question is whether the marketing actually caused additional business.

Imagine Meta reports 1,000 conversions from a campaign. That tells you Meta has attributed those conversions to the campaign according to its own methodology. But how many of those customers would have purchased anyway?

The opposite problem can happen with channels that influence demand earlier in the customer journey. Someone might discover a product through TikTok, search for the brand several days later, and eventually purchase through another channel. Last-click attribution may give TikTok very little credit even though it helped create the demand in the first place.

Neither situation is unusual. It is simply the difference between attribution and incrementality.

For performance marketers making daily budget decisions, the more useful question is not which platform claimed the conversion. It is what actually happened because we invested in the marketing?

Start by proving incrementality

Sellforte Incrementality Testing, available from $1,900 per month, is designed for teams that want to answer that question one experiment at a time.

You might want to understand whether increasing Meta spend generated additional sales, validate the effectiveness of a campaign in a specific market, analyze the results of a Meta Conversion Lift Study, or bring your existing A/B tests into a consistent measurement environment.

Sellforte gives performance teams one place to run and analyze those experiments, including Geo Lift tests, imported Conversion Lift results, and uploaded A/B tests. Teams can measure incremental sales and iROAS, review confidence and model quality, use AI-generated summaries to understand the results, and keep previous experiments together in the Experiments Hub.

The purpose is straightforward: before deciding to scale an investment based on attributed conversions, prove that it is actually creating incremental business impact.

For some teams, that is the measurement problem they need to solve. For others, it is the starting point for something more continuous.

From individual tests to always-on Incremental Attribution

Experiments provide strong evidence, but performance marketers make investment decisions every day. You cannot run a controlled experiment for every campaign, ad set, and budget decision.

Sellforte Incremental Attribution, available from $2,500 per month, builds on Incrementality Testing by making incremental performance an always-on part of the performance marketing workflow.

Sellforte connects media and sales data and measures incremental performance across platforms, campaigns, and ad sets. Instead of relying on separate attribution methodologies from Google, Meta, TikTok, and GA4, marketers get an independent view of how their investments are contributing to the business.

That includes campaign and ad set level incremental attribution, incremental sales, miROAS, and comparisons between platform-reported and incremental performance. Performance teams can use those insights to understand which investments are genuinely driving growth, which may be receiving too much credit, and where additional budget is most likely to create incremental impact.

Every advertising platform can have its own attribution methodology. Your business still has one P&L.

Incremental Attribution gives performance marketers a common basis for comparing those investments.

Two packages for two different measurement needs

We have deliberately separated Incrementality Testing and Incremental Attribution because they solve different jobs.

Incrementality Testing is for teams that want to answer a specific question: did this marketing activity actually create incremental sales?

Incremental Attribution is for teams that need an ongoing answer to a broader question: which parts of our paid media are actually creating incremental sales right now?

Incremental Attribution includes everything in Incrementality Testing because the two approaches are designed to reinforce each other. Experiments provide direct evidence of causality, while Incremental Attribution turns that incrementality foundation into an always-on view of media performance.

This gives ecommerce and DTC teams a more practical way to build their measurement capabilities over time, rather than having to start with the most comprehensive setup from day one.

Building toward Full-Funnel MMM

As ecommerce and DTC brands grow, the measurement questions usually become broader.

It is no longer only about whether Meta, Google, or TikTok is driving incremental sales. Teams also need to understand the impact of promotions, underlying demand, brand marketing, offline channels, external factors, and how all of those drivers interact.

That is where Full-Funnel MMM becomes the natural next step.

Our view is that strong MMM should be built on a solid incrementality foundation. Teams should first establish how they test causality, understand incremental media performance, and use those insights in their decision-making. From there, they can expand into a more comprehensive model of everything driving the business.

The progression is straightforward: start with Incrementality Testing, build into always-on Incremental Attribution, and evolve into Full-Funnel MMM as your measurement needs grow.

You do not need to start with everything. You need to start by answering the most important measurement questions correctly.

Start measuring what your marketing actually adds

Ecommerce performance marketing has spent years optimizing around attribution. But attributed conversions and incremental impact are not the same thing.

Sellforte Incrementality Testing gives teams a way to prove what their marketing actually caused. Incremental Attribution turns that understanding into an always-on view across paid media.

Sellforte Incrementality Testing is available from $1,900 per month and Sellforte Incremental Attribution is available from $2,500 per month.

If you want to move beyond attributed conversions and understand the true incremental impact of your marketing, we can show you how both packages work.

👉 Book a demo to see Sellforte Incrementality Testing and Incremental Attribution in action