What Is NDCG? The Metric That Measures Whether Your Ecommerce Search Actually Works

Normalized Discounted Cumulative Gain (NDCG) is a metric crucial for ecommerce teams wanting to improve search quality by ensuring that the most relevant products appear at the top of search results, where shoppers are most likely to see them. Unlike basic relevance metrics, NDCG takes into account the position of products in search results, assigning more weight to products that appear earlier. This positioning reflects actual shopper behavior, where the initial few results receive most attention. The metric compares the actual order of search results to the ideal order, where the most relevant items are ranked first. Marqo, an AI-native product discovery platform, uses NDCG to enhance its Commerce Superintelligence, outperforming traditional keyword-based search systems by focusing on genuine product understanding rather than mere textual matches. This approach not only boosts NDCG scores but also converts these improvements into measurable revenue gains, as evidenced by Marqo's 88% NDCG improvement over Amazon Titan, demonstrating a significant advancement in product discovery and ecommerce search effectiveness.