What you will learn in this article
- How Ad Rank works in the Google Shopping carousel and why it differs from Search campaign Ad Rank
- The three official factors in Google Shopping ranking: bid, ad quality, and auction context
- The role of the Google Shopping product feed in positioning, and why the title is the most critical attribute
- Undocumented factors that influence Google Shopping positioning, drawn from real account experience
- How PMax and standard Shopping campaigns coexist in the carousel and which tends to prevail
- The most effective operational strategies to optimise Google Shopping, prioritised by their ranking leverage
The Google Shopping carousel, that row of product cards with image, title, price, and store that appears at the top of SERPs for commercial queries, is the most visible and most competitive placement in e-commerce advertising on Google. Unlike organic traffic, which rewards content and domain authority, Google Shopping results are determined by a real-time auction run by the search engine for every query. Shopping search results appear above standard text ads and organic listings, making position in the carousel disproportionately valuable for e-commerce visibility.
The most common misconception is that the carousel is sorted by price (cheapest products first) or by organic relevance (best-selling products first). That is not how it works. The Google Shopping carousel is the result of a real-time auction in which each position is assigned based on an Ad Rank, a score that combines the advertiser's bid with the estimated quality of the ad for that specific query at that specific moment.
Understanding how Google Shopping works at the ranking level has concrete implications for where to invest optimisation time: the feed, the bid, the images, the price. Not all of these factors carry equal weight, and some have a far greater impact than official documentation suggests.
How Ranking in the Carousel Works: The Official Version
According to the official Google documentation on Shopping ads (support.google.com/google-ads/answer/2454022), Google Shopping positioning is determined by Ad Rank, calculated from three components. Shopping ads, also known as product listing ads, differ from Search text ads in that they are assembled automatically from feed data rather than written manually by the advertiser.
The maximum CPC set for the product group, or the automatic bid calculated by Smart Bidding based on the conversion goal. Google uses this as the auction baseline.
Google estimates quality based on three elements: product relevance to the query (determined mainly by the feed), expected CTR (click history vs impressions), and landing page quality (speed, relevance, user experience).
The specific query typed by the user, device, time of day, geographic location, and past user behaviour. This component makes ranking vary auction by auction.
The formula is multiplicative, not additive. Improving product quality by 50% has the same ranking effect as raising the bid by 50%.
What official documentation does not specify: Google does not publish the exact Quality Score formula for Shopping, nor the relative weights of the individual components. We know it exists, we know the three factors, but we do not know whether relevance, CTR, and landing page carry equal weight or different coefficients. This opacity is intentional, Google wants advertisers to optimise all factors simultaneously, not game a single one.
The Product Feed and Ranking: What Actually Matters
The Google Shopping product feed is the central document of ranking. Google uses feed attributes, title, description, category, GTIN, image, price, availability, to determine which queries a product is relevant for, and relevance is the factor with the greatest impact on ad quality and therefore on final ranking.
The title: the most critical attribute for ranking
The title is the attribute with the greatest direct impact on Google Shopping ranking. Google uses it as the primary relevance signal: if the user's query contains words present in the product title, the product is considered relevant for that query. A title that does not contain the keywords relevant to the query will not appear in the carousel for that search, regardless of the bid.
The optimal title structure for Google Shopping positioning follows a precise logic: brand + product name + variant + key attribute. For example: "Nike Air Max 90 Men's White Size 9" instead of "Nike Running Shoe." An optimised title is specific, contains the attributes users search for in the query, and covers the most frequent search variants for that product.
Images: indirect ranking impact via CTR
Images do not directly influence Google Shopping ranking in the strict sense, Google does not explicitly evaluate the aesthetic quality of the image in Ad Rank. But high quality images influence CTR, and CTR is one of the ad quality components that enters Ad Rank. A cleaner, more attractive image generates more clicks per impression, improves the product's historical CTR, and therefore improves ad quality over time.
GTIN and technical attributes: relevance and feed quality
The GTIN (EAN/UPC code) is one of the most underestimated attributes for Google Shopping ranking. Providing the correct GTIN allows Google to match the product against its internal catalogue, with all associated additional information (aggregated customer reviews, variants, competitor price history). Products with a correct GTIN configured in the Google Merchant Center account tend to receive impressions for more specific queries and have a structurally higher average CTR than the same products without GTIN.
Undocumented Factors That Influence Ranking
Google does not document the complete formula for Google Shopping ranking. From experience on real accounts, positioning patterns emerge that suggest the existence of additional factors beyond the three official ones. None of these are confirmed by Google, they are operational inferences based on repeated, controlled observations across multiple accounts.
Competitive pricing relative to competitors
Google has access to the prices of all Shopping advertisers for every product. There is operational evidence, but no official documentation, that products priced significantly above the competitor average for the same GTIN receive fewer impressions for the same queries, regardless of bid. The hypothesised mechanism is that Google estimates a lower expected CTR for products with an uncompetitive price, which lowers the estimated Quality Score.
Account and product history
As in Search campaigns, Google considers the performance history of the account and of the individual product in calculating Quality Score. Products that have historically generated high CTR and high conversion rates tend to receive a better Quality Score for the same queries, even when the bid is unchanged. This creates a "rich get richer" effect: products that perform well receive more impressions, generate more data, and their Quality Score continues to improve over time.
Coherence between feed, landing page, and price
Google checks coherence between the information in the feed and that on the product's landing page. A different title, different price, or different availability between feed and landing page are negative signals that lower ad quality, and can lead to disapproval of the product in Merchant Center. Landing page speed, clear purchase information (visible price, working cart, stated shipping) also contribute to the destination page quality score.
How to Optimise Google Shopping: Operational Strategies for Ranking
Effectively optimising Google Shopping means intervening on the factors with the greatest ranking leverage, in the correct order. From highest to lowest leverage:
- Feed and titles as the absolute priority. If product titles do not contain the relevant attributes for the target queries, no bid can compensate. The first action on a Shopping account with low performance is almost always rewriting titles following the brand + product + variant + attribute structure. The ranking impact is visible within 2–4 weeks without touching the bid.
- GTIN and complete technical attributes. Complete the Google Shopping product feed with correct GTINs, standardised colours, sizes in the correct format, and precise Google Product Taxonomy categories. Missing or imprecise attributes limit the queries for which the product can appear in the carousel.
- Images optimised for CTR. Test different images on the same products, white background vs lifestyle, square vs rectangular format. Monitor per-product CTR in the Shopping report to identify which image type performs best in the product's category.
- Choose the right bidding strategy for each product segment. Not all products have the same strategic priority. Use custom labels in the feed to segment products into groups (high margin, bestsellers, end of season) and apply different bids per group. Google Shopping bid ranking should not be managed flat across the entire catalogue.
- Competitive pricing monitored actively. Use tools like Google Merchant Center Price Competitiveness or repricing solutions to keep prices within the competitive range for the main categories.