Case Study E-Commerce Paid Advertising Tracking & Analytics

From Blind Spending to Margin-Positive Growth.

How we rebuilt the measurement and paid media architecture for a French home & décor e-commerce brand spending €150K/month on Google Ads alone — over €200K/month across all channels — and uncovered a third of their conversion value that Smart Bidding couldn’t see.

€150K
Monthly Google Ads Spend (€200K+ across all channels)
+50%
Gross Margin Growth Year over Year
3.0x
Margin ROAS target applied across every campaign — PMax, Shopping, Search, and Demand Gen — high-margin products prioritised at every level
34%
Of revenue driven by products invisible to Google's attribution — uncovered and corrected

The Client

A French home & décor e-commerce brand with a broad product catalogue, selling across France and Western Europe. They were spending €150,000 per month on Google Ads alone — over €200,000 per month across Google, Meta, Microsoft, and TikTok combined — primarily through Performance Max campaigns, legacy search campaigns, and Shopping — and had been growing their ad budget year-on-year without a clear picture of what was actually working.

The brand came to us with a straightforward ask: explain why ROAS feels wrong, and fix it.

The Challenge

When we ran the initial audit, we found three compounding problems:

  • Conversion tracking was measuring revenue, not margin. The primary conversion action feeding Smart Bidding was tracking gross merchandise value (GMV) — not the brand’s actual gross margin. Smart Bidding was optimising for the wrong number, inflating apparent ROAS while masking genuine profitability.
  • Performance Max was running unconstrained. 96 asset groups across the main PMax campaign had no target ROAS set. Two campaigns were operating below the 3.0x margin ROAS breakeven point, burning money with no automated brake.
  • Browse-trigger products were invisible to Smart Bidding. A significant portion of the catalogue drove high browsing traffic and contributed to sessions that ended in purchase — but because the purchase was attributed to a different product, Smart Bidding was suppressing these “browse trigger” products. We suspected this was hiding substantial value.
“Smart Bidding was optimising for a number that didn’t match the business. Before we could improve performance, we had to fix what ‘performance’ meant.”

The Solution

We approached the rebuild in three phases:

Phase 1: Conversion tracking rebuild. We identified the correct gross margin conversion action and re-mapped it as the sole Smart Bidding signal. We documented the break-even point (3.0x margin ROAS) and aligned all optimisation logic around it.

Phase 2: Full account restructure. We rebuilt the campaign architecture across PMax, Shopping, Search, and Demand Gen around a single 3.0x margin ROAS break-even target. High-margin products were prioritised at every level. All 96 PMax asset groups received explicit tROAS constraints aligned to product category margin rates. We fixed 27 asset groups with broken final URLs pointing to discontinued sale pages, and paused the two confirmed below-breakeven campaigns.

Phase 3: Browse trigger pipeline. We built a custom attribution pipeline joining Google Ads product-level data with GA4 BigQuery session sequences. This let us identify products that consistently appeared early in browsing sessions that ended in purchase — and calculate their true session-level contribution value.

  • GA4 BigQuery export analysis to reconstruct CPC session paths
  • Product-level ROAS recalculation: direct vs. session-assisted ROAS
  • Automated monthly pipeline to refresh browse trigger scores
  • tROAS recommendation engine with confidence thresholds

The Results

Within 60 days of implementation, the data told a materially different story:

+50%
Gross margin growth year over year — driven by margin-first measurement and smarter bid allocation
34%
Of revenue driven by products invisible to Google's attribution — uncovered and corrected
27
PMax asset groups with broken URLs fixed, recovering lost traffic and improving Quality Score
3.0x
Margin ROAS break-even target applied across the full account — PMax, Shopping, Search, and Demand Gen restructured to prioritise high-margin products

Beyond the headline numbers, the brand now has a measurement architecture they can trust. Every euro of ad spend maps to a margin outcome. The browse trigger pipeline runs automatically on the 1st of each month, surfacing new bid recommendations without manual analysis.

The biggest win wasn’t a metric — it was clarity. The brand can now make budget decisions based on real profitability, not platform-reported ROAS.

What’s Next

We are currently extending the engagement to cover Meta Ads and Microsoft Ads, applying the same margin-first measurement framework across channels. A cross-channel attribution model is in development to bring the full paid media picture into a single Looker Studio dashboard, updated daily via BigQuery.

Want the Same Clarity for Your Brand?

We’ll start with an honest audit of your current measurement setup. If there’s hidden value in your data, we’ll find it.

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