And how to use AMC to measure it! Because ROAS alone can’t tell you whether your ads created new demand…
For years, Amazon advertisers have relied on campaign-level metrics to gauge their performance on Amazon and while this is obviously useful, it’s not actually complete.
Yes, traditional PPC reporting does show you what happened after your spend was deployed – the clicks, the conversions and the ROAS.
But it trips at the hurdle of one of the most important commercial questions; “what would have happened if we hadn’t spent that money?”
This is the incrementality gap – and it’s where Amazon Marketing Cloud (AMC) is a gamechanger.
Here, inspired by this post from Venture Forge Paid Ads guru Elfie Brocklehurst, we explore how to quantify your incremental impact, and how those stats combine with your attributed impact so you can confidently judge the true value of your media mix.
Why it Matters
Without knowing whether those new sales would have happened whether you’d just spent on Ads or not, your brand risks:
- Over-investing in tactics that inflate ROAS but don’t grow your business.
- Under-investing in mid and upper-funnel activity that drives long-term scale.
- And misreading your performance data because your attribution is too narrow.
What AMC makes possible
As Elfie points out, AMC gives you the tools to shift your reporting from performance to proven business impact.
Because it connects signals across Sponsored Ads, DSP, audiences and conversions, you can use its event-level, privacy-safe data to bridge the incrementality gap and reveal real cause and effect – analysing in a way that’s just not possible inside the standard ads console.
With AMC, brands can:
- Measure incrementality by comparing exposed vs. unexposed audiences, helping to determine whether spend truly creates new demand.
- Analyse cross-channel “halo effects” to understand how DSP, Sponsored Brands and Sponsored Products influence each other along the path to purchase.
- Map multi-touch journeys, identifying the sequences of ad exposures that happen before a conversion.
- Pinpoint inefficiencies and cannibalisation, spotting where spend captures demand that may have converted without paid media.
- Test sequencing strategies, evaluating which combinations of ads move customers from first exposure to final purchase.
- And validate new-to-brand performance, using clean-room data to assess which campaigns genuinely drive first-time buyers.
What should you do now?
Start measuring incrementality, not just ROAS
Use AMC to understand what each pound of spend genuinely adds.
Analyse audience journeys
Identify which combinations of DSP, SB and SP move your customers through the funnel.
Test media sequences
Discover which order of exposures drives the highest incremental conversion.
Reduce cannibalisation
Spot campaigns that just harvest demand that’s already there, as opposed to generating new growth.
Invest more confidently in Amazon Ads
Use your AMC findings to scale the activities that are genuinely delivering you sales, not just good attribution numbers.
The Bottom Line
Incrementality is the metric that separates efficient advertising from genuinely effective advertising – and AMC has the tools you need to measure it properly, no guesswork needed.
For advertisers serious about growth? We think it’s one of the key foundations of a smarter, commercially sharp media strategy.
Need support to drive true impact from your Amazon Ads strategy? Our award-winning Paid Ads team is on hand to help – click here to get in touch today.