Fospha Masterclass Recap: Unlocking the Halo Effect

On Monday last week, Fospha delivered an eye-opening masterclass at SXSW, unveiling new insights into the elusive Halo effect — the connection between off-platform advertising (on TikTok, Meta, Google, and others) and Amazon sales.

Dom Devlin, CPO of Fospha, led the session, sharing groundbreaking research that proves how external ad investments directly drive Amazon growth — and how brands can measure and optimize this impact.

🎯 Key Takeaways

1. The Problem: The Amazon Measurement Gap

Amazon accounts for 40% of US e-commerce sales, yet many marketers struggle to accurately measure the impact of off-platform ads on Amazon conversions.

Traditional measurement tools like Multi-Touch Attribution (MTA) and Amazon Attribution tend to over-index on last-click data, disproportionately crediting lower-funnel tactics and overlooking upper-funnel brand-building efforts.

As a result, significant revenue is often misattributed, leading marketers to undervalue key awareness-driving platforms like TikTok, YouTube, and Meta.

2. Introducing Fospha’s Solution: Unified ROAS

Fospha’s new Unified ROAS (UROAS) metric offers a comprehensive view of total revenue — combining both DTC and Amazon sales data to reflect the full impact of media spend.

Unlike traditional attribution methods, UROAS blends Fospha’s machine learning (ML) model with a daily media mix model (MMM) to account for both click-based data and upper-funnel influence.

With this new approach, Fospha has identified that 42% of Amazon sales are influenced by non-Amazon media — a significant insight for brands investing heavily in awareness campaigns.

3. Why UROAS is Different

Fospha’s ability to offer UROAS hinges on their unique methodology:

• Click Attribution with ML Modeling: Fospha models available click data but also extends insights beyond traditional attribution by recognizing and accounting for organic conversions influenced by upper-funnel campaigns.

• Daily MMM Calibration: Fospha’s MMM dynamically recalibrates every month, ensuring that the model accurately reflects performance across diverse campaign types and media platforms.

4. Key Insights for Amazon Marketers

Fospha’s data shows that platforms like TikTok and YouTube are undervalued in traditional attribution models. With UROAS, these platforms saw a significant uplift in their contribution to overall revenue.

For example, Fospha’s analysis showed that brands using TikTok as part of their marketing strategy achieved a 2.8 ROAS (previously thought to be just 2.1 before UROAS insights were applied). This uplift indicated substantial headroom for scaling spend on TikTok.

5. Case Study: Nécesaire Prime Day Success

Fospha’s client, Nécesaire, used Halo insights to scale TikTok spend ahead of Amazon Prime Day. By recognizing the true impact of TikTok on Amazon conversions, Necessary achieved:

• 50% higher revenue growth compared to non-Fospha Amazon brands.

• Their highest revenue day ever, surpassing internal forecasts.

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🚀 @Amazon ads: what you’re missing 🛒 For years, Amazon has been a black box - but what if your Meta ads were driving more impact than you ... See more

6. Strategic Recommendations from Fospha

Dom and Jamie emphasized key strategies for marketers aiming to improve Amazon performance:

• Invest Early in Upper Funnel Campaigns: Building brand awareness months ahead of key events like Prime Day or Black Friday ensures stronger demand capture later. TikTok and YouTube were highlighted as crucial awareness-building platforms.

• Balance Upper Funnel with Efficient Lower Funnel Spend: Fospha’s “Spend Strategist” tool helps brands identify how to scale efficiently without inflating customer acquisition costs (CAC).

• Data-Driven Decision Making: Unified ROAS enables marketers to confidently scale awareness campaigns with clear data insights, reducing the risk of over-reliance on last-click data.

Final Thoughts: Why It Matters

Fospha’s Halo product is redefining measurement for brands selling on Amazon. By bridging the measurement gap between off-platform media and Amazon conversions, Fospha empowers marketers to make smarter, data-driven investment decisions — ultimately driving more effective upper-funnel campaigns and improved ROI.

For brands looking to scale efficiently and win big on Amazon, Unified ROAS offers a powerful new approach to unlocking hidden growth opportunities.

📘 Unlock the Full Amazon Opportunity

Fospha’s Halo Report distils all of these insights — measurement strategies, budget allocation recommendations, creative best practices, and more — into a single resource.

👉 Download the Ultimate TikTok Playbook Here

🎉 Join Us at Shoptalk Spring in Vegas

Fospha will be hosting a series of exclusive masterclasses at Shoptalk Spring in Las Vegas from March 25–27, 2025. Learn more about full-funnel measurement, cross-platform impact, and the latest TikTok strategies.

👉 Explore Fospha’s Shoptalk Spring events → See the Schedule

Stay tuned for more insights from Fospha’s SXSW Masterclass Series,
The Unofficially SXSW Team

📢 Unofficially SXSW is an independent publication and is not affiliated with SXSW.

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