Shopping Campaign Structure · Product Groups & Bidding

Google Ads offers two campaign types for Shopping: Standard Shopping and Performance Max (PMax). Understanding when each is appropriate determines both control level and performance potential.

Most experts recommend starting with Standard Shopping to build conversion data and understand product performance before transitioning high-performing product groups to Performance Max.

The primary reason to segment products into separate campaigns is differentiated bidding — products with different profit margins require different ROAS targets. A product with 60% gross margin and a product with 15% gross margin cannot share the same ROAS target and remain profitable.

Segmentation by margin tier

Use custom_label_0 in the product feed to tag products by margin tier (High, Medium, Low). Create separate campaigns for each tier with different Target ROAS values. High-margin products can afford lower ROAS targets (spending more per £1 of revenue); low-margin products need higher ROAS targets to maintain profitability.

Segmentation by performance

After accumulating Shopping performance data, create a tiered structure: top-performing products (high ROAS, high volume) in a "hero" campaign with aggressive bidding; mid-performing products in a standard campaign; untested or poor-performing products in a catch-all campaign with conservative bids.

Brand vs non-brand campaigns

Searchers who include your brand name in their Shopping query have higher purchase intent and higher conversion rates. Separate brand-name Shopping queries into their own campaign using campaign priority settings — this allows different ROAS targets and budget allocation for brand searches.

Within a Shopping campaign, the product group hierarchy determines bid granularity. At the top is "All Products" — one bid applied to everything. You subdivide this by product attributes to apply more granular bids:

All Products (campaign default bid: £0.50)
├── Category: Running Shoes (bid: £0.80)
│   ├── Brand: Nike (bid: £1.20)
│   │   └── Item ID: [individual products] (bid: per product)
│   ├── Brand: Adidas (bid: £1.00)
│   └── Brand: All other (bid: £0.70)
├── Category: Trail Running Shoes (bid: £0.90)
└── Category: Everything else (bid: £0.40)

Subdivision attributes available: Category (Google product category), Brand, Item ID (individual product), Condition, Product Type, Custom Label (0–4), Channel, Channel Exclusivity.

The most granular level — Item ID subdivision — allows a different bid for every individual product. This is impractical to set manually for large catalogues but is achievable through Smart Bidding where Target ROAS bidding automatically adjusts per product based on conversion probability.

Shopping campaigns support the same bidding strategies as Search: Manual CPC, Enhanced CPC, Target ROAS, Maximise Conversion Value.

Manual CPC for Shopping provides granular control at the product group level — you set a different max CPC for each product group subdivision. This is the best starting strategy for new Shopping campaigns without conversion data, allowing you to understand performance by product category before switching to automated bidding.

Target ROAS is the recommended Smart Bidding strategy for mature Shopping campaigns. It maximises conversion value at your specified ROAS target — automatically bidding more on products that are more likely to convert at profitable values. Requires 50+ Shopping conversions per month with accurate revenue values in conversion tracking.

Shopping campaign priority (Low, Medium, High) determines which campaign's bid is used when multiple campaigns contain the same product. This is critical for the brand vs non-brand segmentation strategy:

• High priority campaign — catches all traffic first. Set with broad product targeting and a low bid. This campaign serves as the "catch-all" for any query, competing with a conservative bid. The low bid means it will often lose auctions to higher-bidding competitors.
• Medium priority campaign — contains branded products. Wins over the high-priority campaign when a branded query triggers both, because the medium campaign's bid is higher (brand searches convert better).
• Low priority campaign — contains top-performing products with aggressive bids. Loses to higher priority for most queries, but wins when the query is highly specific to those products.

This creates a funnel structure: generic queries use conservative bids; brand-specific queries use medium bids; highly specific product queries use aggressive bids.

• Search Terms report. Identify irrelevant queries in Shopping Search Terms and add negatives. Shopping negatives are applied at campaign level. High-volume irrelevant traffic in Shopping often comes from generic product type queries — add these as exact match negatives.
• Product performance data. Review ROAS and conversion rate by product group and individual product. Increase bids for high-ROAS products; reduce or pause bids for chronically low-ROAS products.
• Impression share. Low impression share with high ROAS indicates you could profitably increase bids or budget to capture more available traffic. High impression share with poor ROAS indicates over-bidding or poor product/audience fit.
• Feed quality maintenance. Disapproved products and feed errors reduce impression share invisibly — products that could serve are silently excluded. Weekly feed quality checks prevent gradual erosion of campaign scale.

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