Is a Bigger Catalogue Always Better?
The conventional wisdom in Google Shopping is that more products means more opportunities — more search term coverage, more impression share, more potential conversions. This is partially true. But it ignores the cost dimension.
Adding more products to a Google Shopping campaign increases:
- Feed management complexity (more products to keep accurate and optimised)
- Budget dilution (the same budget spread across more products means less per product)
- Risk of margin-negative spend (if low-margin products receive the same ROAS target as high-margin ones)
- Smart Bidding confusion (signals diluted across more products with less data per product)
The question isn't "how many products should I advertise?" — it's "which products generate positive return on ad investment, and am I investing proportionally in them?"
| Catalogue Size | Key Challenges | Best Strategy |
|---|---|---|
| Thin (under 100 SKUs) | Limited search coverage; vulnerable to category changes | High-quality feed for every product; margin-based bids |
| Mid-size (100–1,000 SKUs) | Manual management feasible but time-consuming | Margin tier campaigns or SPAG for top 50 products |
| Wide (1,000–10,000 SKUs) | Manual per-product management impossible | Automated SPAG structure; margin-based bid automation |
| Enterprise (10,000+ SKUs) | Feed quality + per-product bidding requires automation | Full automation essential — GROW Platform or similar |
The Pareto Principle in Google Shopping
The Pareto principle (80/20 rule) consistently holds in e-commerce product performance. An analysis of Shopping catalogue performance typically reveals:
- 20% of SKUs generate 80% of Shopping revenue
- An even more concentrated pattern for profit: 15% of SKUs generate 85% of gross profit
- Some products in the catalogue may generate negative profit contribution after advertising costs
Pareto Analysis: Sportswear Brand, 800 SKUs
Analysis results:
- Top 160 SKUs (20%): £485,000 gross profit from Shopping (82% of total)
- Mid 320 SKUs (40%): £95,000 gross profit (16%)
- Bottom 320 SKUs (40%): £12,000 gross profit (2%) — some at break-even or loss
Implication: Improving feed quality and increasing bids for the top 160 SKUs by 30% would have far more impact than any optimisation applied to the bottom 320 SKUs — while also freeing budget from poor performers.
How to Run Your Pareto Analysis
- Export Google Ads data: spend, conversions, and revenue by product ID (90-day window minimum)
- Export COGS data for the same products from your systems
- Calculate gross profit per SKU: (revenue × gross margin) − ad spend
- Rank all products by gross profit descending
- Identify: top 20% stars, middle 60% potential, bottom 20% underperformers
Feed Quality vs Quantity
Feed quality is the ceiling on per-product Shopping performance. No amount of budget overcomes a poor product listing. The hierarchy of investment should be:
Priority 1: Excellent feed quality for top 20% Pareto products
Priority 2: Good feed quality for mid-tier products
Priority 3: Adequate (auto-generated or minimal) for bottom-tier products that only need organic impression coverage
Feed Quality Factors That Drive Performance
| Feed Element | Impact | Improvement Effort |
|---|---|---|
| Product title | High — directly affects search match | Medium (rewrite key attributes) |
| Primary image quality | High — affects CTR significantly | High (photography investment) |
| GTIN accuracy | High for branded products | Low (data lookup) |
| Product description | Medium — affects long-tail match | Medium |
| Product type taxonomy | Medium — affects category relevance | Low |
| Additional images | Medium — improves CTR | High (photography) |
| Price competitiveness | High — Google benchmarks against competitors | Strategic decision |
For large catalogues, prioritise feed quality improvements on your Pareto top 20% first. Even 10 hours of feed optimisation applied to your top 50 products will outperform the same effort spread across 500 products.
Filtering Unprofitable Products from Shopping Campaigns
Products that consistently generate negative contribution margin from Shopping — even before considering fixed overheads — should be managed carefully. You have three options:
Option 1: Exclude from Paid Campaigns (Keep Organic)
Remove from paid Shopping campaigns entirely but keep the product in Merchant Center for organic Shopping exposure. These products continue to appear in the free Shopping tab without generating paid cost.
Option 2: Apply Conservative Bid Cap
Keep in campaigns with a very high ROAS target that effectively limits paid impressions to only the most cost-efficient auctions. In practice, this means the product bids very low and only wins when competition is minimal.
Option 3: Full Delist for Very Low-Margin Products
Products with margins below 10% that also have no strategic cross-sell or anchor role may be worth delisting from Shopping entirely — they consume feed management overhead without meaningful return.
Keep Organic, Control Paid
The default position for low-performing products: maintain their Merchant Center listing for organic Shopping visibility (free), but exclude them from paid campaigns. This captures any organic demand without the cost of paid competition.
SPAG Architecture for Large Catalogues
Single Product Ad Groups (SPAGs) give each product its own ad group with its own ROAS target. This is the gold standard for large catalogue management — but the complexity scales with catalogue size.
Practical SPAG Implementation by Scale
- Under 100 products: Manual SPAG creation feasible. Use shared campaign with one ad group per product.
- 100–500 products: Semi-automated using Google Ads Editor scripts or templated bulk uploads.
- 500–5,000 products: Automation essential. Custom scripts or a platform like GROW required.
- 5,000+ products: Full API-based automation only viable option. GROW Platform handles up to 1M+ products per account.
When SPAGs Aren't Worth the Effort
For products generating fewer than 5 conversions per month, a full SPAG with individual tROAS optimisation provides limited benefit — Smart Bidding can't learn from 5 conversions. Group similar-margin, similar-category products together for better learning signal in these low-volume cases.
GROW Platform's Automatic Product-Level Bidding for Large Catalogues
Managing per-product ROAS targets across a catalogue of thousands of products is effectively impossible manually. GROW Platform solves this through complete automation:
- Automatic SPAG generation: Build and deploy SPAG campaigns for your entire catalogue via Google Ads API in minutes
- Per-SKU ROAS target calculation: ProfitClarity calculates a unique ROAS target for every product based on its MarginStack cost data and your configured profit target
- Dynamic bid updates: When COGS data changes (supplier price update, currency shift), affected product ROAS targets automatically recalculate and bids update
- Performance monitoring: Identify products where actual ROAS consistently exceeds or falls below target, flagging opportunities for bid adjustment or investigation
- Automatic product discovery: New products added to your Merchant Center feed are automatically detected and can be deployed to campaigns without manual campaign creation
Frequently Asked Questions
Is a larger product catalogue always better for Google Shopping?
Not always. A large catalogue with inconsistent feed quality often underperforms a smaller, well-optimised feed. More importantly, advertising low-margin products dilutes budget and can reduce overall account profitability. The question isn't size — it's which products deserve advertising investment.
What is the Pareto principle in the context of Google Shopping?
The Pareto principle (80/20 rule) applied to e-commerce typically shows that 20% of SKUs generate 80% of revenue and an even higher proportion of profit. Identifying these top performers and optimising feed quality and bids for them disproportionately improves account performance.
Should I advertise every product in my catalogue on Google Shopping?
Not necessarily. Products with margins below 15% typically cannot be profitably advertised. Products with very low search volume waste Smart Bidding learning. The recommended approach: advertise all products but apply margin-based ROAS targets — this naturally concentrates spend on profitable products automatically.
How do I identify my top 20% of SKUs by profit?
Export your orders for the past 12 months. Calculate gross profit per SKU (revenue × gross margin). Sort descending. The top 20% of SKUs by gross profit are your priority products. These deserve superior feed quality (more images, detailed descriptions, competitive pricing) and aggressive bid targeting.
How does GROW Platform handle large catalogue bidding?
GROW creates individual ad groups (SPAGs) for each product with unique ROAS targets calculated from its margin data. At 1M+ SKU scale, this is only possible through automation. The system automatically focuses spend on high-margin products and restricts spend on low-margin ones without manual management.
Next Steps
Run your Pareto analysis this week. Identify your top 20% of SKUs by gross profit. Audit their feed quality. These are the products that deserve your best images, most optimised titles, and most aggressive bids — whether you have 100 products or 100,000.
Automate Per-Product Bidding at Any Scale
GROW Platform builds and manages SPAG campaigns with per-SKU ROAS targets across catalogues of any size — from 100 products to 1 million. Create an account to get started →
