Shopify + Google Ads Attribution: Beyond Last-Click ROAS
Google Ads takes credit for every branded search purchase. Causality Engine reveals which Google campaigns create new demand vs. which just capture existing intent.
Channel comparison
Google Ads: reported vs. actual contribution
What Google Ads claims vs. what causal inference reveals
Why Google Ads over-reports
- Branded search captures existing demand, customers who would've bought anyway get attributed to Google
- Google's data-driven attribution model is a black box that still favors Google channels
- Last-click attribution gives Google 100% credit when it's the final touch, ignoring discovery channels
- Smart Bidding optimizes for Google's attribution model, not your actual incrementality
- Shopping campaigns get credit for price-comparison clicks that would've happened organically
The hidden cost
Of Google Brand Search ROAS comes from demand other channels created
How Causality Engine fixes Google attribution
- Separates branded search (demand capture) from non-branded (demand creation), see true incremental ROAS
- Causal inference measures what would've happened WITHOUT Google Ads, the real test of value
- Cross-channel Shapley values show Google's true contribution alongside Meta, TikTok, and email
- Identifies which Google campaigns create new customers vs. which cannibalize organic traffic
- No dependency on Google's attribution model, independent measurement from your own data
GA4 CSV upload
Connect your Shopify store
One-click OAuth. Read-only order data access.
Link your GA4 property
We analyze session data across all channels, not just Google.
See real Google Ads incrementality
Discover which campaigns actually create demand vs. capture it.
Google Ads: at a glance
| Metric | Google Ads reports | Causal truth |
|---|---|---|
| ROAS | 8.5x | 3.1x |
| Tracking method | Pixel + modeled | Causal inference |
| Pixel required? | Yes | No |
| iOS impact | 40-60% data loss | Zero impact |
| Setup time | 1-2 hours | 5–10 min (GA4 CSV upload) |
Frequently asked questions
Can Causality Engine separate branded vs. non-branded Google Ads impact?
Yes. Our causal model distinguishes between campaigns that create new demand (non-branded, Discovery, YouTube) and those that capture existing demand (branded search, Shopping). This is critical for budget allocation.
Does this replace Google Analytics attribution?
It complements it. GA4 tells you what happened (which channels touched which users). Causality Engine tells you what caused what, which channels actually drove incremental sales that wouldn't have happened otherwise.
How does this work with Performance Max campaigns?
Performance Max is a black box inside Google. Causality Engine measures the total causal impact of your PMax spend from the outside, using your GA4 and Shopify data. You'll see whether PMax is truly incremental or just re-targeting existing demand.
Do I need to share my Google Ads account?
No. We only need your GA4 property and Shopify connection. We measure Google's impact from your own analytics data, not from Google's ad platform.
Real reports on google-ads
See attribution reports from brands on google-ads.
Anonymised reports from Ecommerce brands running their attribution on google-ads. Per-channel incremental ROAS with confidence intervals.
Browse all google-ads reports →Last-click guesses.We run the math.
Causal attribution for Shopify brands. Upload your GA4 export, see which channels really drove revenue in 5–10 minutes. €99, pay-per-use. Pro at €299/mo when you want it continuous.
The math behind your marketing.
Built for Ecommerce brands using GA4.
Product
Causal AttributionIncrementality TestingMarketing Mix ModelingHow It WorksPricingCompare PlansIntegrationsCase StudiesAttribution LibraryResourcesAttribution GuideDTC PlaybookAd Spend CalculatorHave an idea?
© Copyright 2026, Causality Engine
Based in the Netherlands
|KVK: 92226892
|VAT: NL865944039B01