Module 10 · Lesson 2
Closed-Loop & Omnichannel Attribution
What you’ll learn
- What closed-loop attribution actually does
- How Walmart attributes in-store sales to online ads
- The in-store sales metrics to know
- Why omnichannel ROAS is higher than online-only
This is Walmart’s single biggest measurement advantage — and something Amazon can’t fully match. Because Walmart sells online and in thousands of stores, it can connect an ad to a real purchase wherever it happens.
What closed-loop means
Closed-loop attribution ties ad exposure directly to actual transactions — not modelled estimates. When a shopper sees or clicks your ad and then buys, Walmart connects that sale back to your campaign, across both online and in-store channels.
The online-to-offline bridge
The standout capability: in-store sales attribution for search ads. A shopper clicks your online ad, then buys the product at a physical Walmart — and that in-store purchase is credited to your campaign. Traditional digital advertising simply can’t see that.
The in-store sales metrics
Walmart breaks in-store impact into distinct measures:
In-Store Advertised Sales
A shopper clicks your ad, then buys that exact product in a store.
In-Store Other Sales
A shopper clicks your ad, then buys a different product from your brand in store — the halo effect.
Together with your online orders, these give a fuller picture of what your advertising truly drove.
Omnichannel ROAS
Once you count in-store, your true return looks different:
Omnichannel ROAS = (Online + In-Store + Pickup + Delivery) ÷ Ad Spend
Including in-store sales typically lifts measured ROAS by around 20%, and some brands see 30%+. If you only look at online ROAS, you’re systematically undervaluing your Walmart advertising.
A note on attribution windows
Attribution windows define how long after an ad exposure a sale still counts. Walmart (like the industry) has been moving from fixed windows toward more signal-based, machine-learning credit. The practical takeaway: know which window your reports use when comparing numbers, and expect the methodology to keep evolving — check current definitions rather than assuming a fixed rule.
Quick recap
- Closed-loop attribution ties ads to real transactions, online and in-store — not estimates.
- In-store sales attribution credits physical-store purchases back to your online ads.
- Know the in-store metrics: In-Store Advertised Sales and In-Store Other Sales (halo).
- Omnichannel ROAS (adding in-store) typically runs ~20–30% higher than online-only.