--- title: "Address item_id Issues in the Product Catalog" slug: "address-itemid-issues-in-the-product-catalog-smart-recommender" description: "Learn how mismatched item_id values between system rules and your product catalog break Smart Recommender recommendations, and how to fix them." tags: ["item_id issues", "item_id"] updated: 2026-11-06T08:07:50Z published: 2026-11-06T08:07:50Z canonical: "academy.insiderone.com/address-itemid-issues-in-the-product-catalog-smart-recommender" --- > ## Documentation Index > Fetch the complete documentation index at: https://academy.insiderone.com/llms.txt > Use this file to discover all available pages before exploring further. # Address item_id Issues in the Product Catalog Smart Recommender identifies and ranks the products in your Product Catalog by their **item_id**. When the item_id in your XML feed differs from the one your system rules collect, or when several products share one **item_id**, the algorithms cannot connect analytics data to the right product. As a result, recommendations fail or show products that do not reflect real performance. This article explains how Smart Recommender uses item_id, the two most common **item_id** issues, and how to fix each one. > [!NOTE] > Before you begin, make sure you are familiar with the following articles: > > - [Product Catalog](https://academy.insiderone.com/docs/product-catalog) > - [Decide Your Product Catalog Structure](https://academy.insiderone.com/docs/decide-your-product-catalog-structure) This article covers the following topics: - [How Smart Recommender uses item_id](/v1/docs/address-itemid-issues-in-the-product-catalog-smart-recommender#how-smart-recommender-uses-itemid) - [Issue 1: item_id mismatch between your XML feed and system rules](/v1/docs/address-itemid-issues-in-the-product-catalog-smart-recommender#issue-1-itemid-mismatch-between-your-xml-feed-and-system-rules) - [Issue 2: Several products share one item_id](/v1/docs/address-itemid-issues-in-the-product-catalog-smart-recommender#issue-2-several-products-share-one-itemid) - [Check your item_id setup](/v1/docs/address-itemid-issues-in-the-product-catalog-smart-recommender#check-your-itemid-setup) ## How Smart Recommender uses item_id Smart Recommender reads item_id from two sources: - **XML feed:** Adds and updates products in your Product Catalog. - **System rules:** Collect the **item_id** on your website and pass it with analytics events such as purchases and page views. The algorithms use **item_id** to link these analytics events to catalog products, then identify and rank products such as top sellers, best matches, and category leaders. Insider One identifies each product by its **item_id** and locale together. For recommendations to work, two conditions must be true: - The same product has exactly the same **item_id** in your XML feed and in your system rules. - Each product and each variant has its own **item_id** within a locale. When either condition fails, you see one of the issues below. ## Issue 1: item_id mismatch between your XML feed and system rules ### Symptoms - Smart Recommender shows no recommendations, or shows poor-quality recommendations that do not reflect real product performance. - Products update correctly through your XML feed but have no analytics history. These products are known as *ghost products*. ### Cause Analytics events are attributed to products by the **item_id** that system rules collect. When this value differs from the **item_id** in your XML feed, the events cannot be linked to the correct catalog product. ### Impact - Ghost products have no analytics history, so the algorithms cannot score them. - The algorithms cannot correctly identify top sellers, best-matching products, or category leaders. ### How to fix 1. Update your XML feed so that each **item_id** exactly matches the value your system rules collect and pass. 2. Allow time for the catalog sync and algorithm jobs to run before you check the result. 3. Go to the Recommendation Algorithms page and confirm that the feed is populating. For details, see [Recommendation and Algorithm Settings](https://academy.insiderone.com/docs/recommendation-and-algorithm-settings). Once the values match: - Analytics events are attributed to the correct catalog products. - Algorithms receive accurate data to generate and rank recommendations. - Top seller and category-based algorithms reflect actual product performance. ## Issue 2: Several products share one item_id ### Symptoms - A product shows another variant's price or stock. - Recommendations are less accurate. - Price Drop journeys use a price that belongs to a different variant. ### Cause Insider One identifies each product by its **item_id** and locale together. When you send two products with the same **item_id** in the same locale, Insider One stores them as one product. The values sent last replace the earlier ones, which affects every feature that uses your catalog. ### How to fix 1. Give each product and each variant, such as a different color or size, its own **item_id**. 2. Give all variants of the same product one shared groupcode. For more information on structuring products and variants, see [Decide Your Product Catalog Structure](https://academy.insiderone.com/docs/decide-your-product-catalog-structure). ## Check your item_id setup Use this checklist to prevent both issues: - Each item_id in your XML feed exactly matches the value your system rules collect. - Each product and each variant has its own **item_id** within a locale. - Variants of the same product share one groupcode. ## Related articles Aligned **item_id** values keep your catalog, analytics, and recommendations accurate. As a next step, see [Handle Out-of-Stock Items](https://academy.insiderone.com/docs/handle-out-of-stock-items). - [Product Catalog](https://academy.insiderone.com/docs/product-catalog) - [Decide Your Product Catalog Structure](https://academy.insiderone.com/docs/decide-your-product-catalog-structure) - [Recommendation and Algorithm Settings](https://academy.insiderone.com/docs/recommendation-and-algorithm-settings) - [Resolve the No Feed Error](https://academy.insiderone.com/docs/resolve-the-no-feed-error) ## Related - [Product Catalog](/product-catalog.md)