Multi-objective Ranking Optimization for Product Search Using Stochastic Label Aggregation (Amazon Science, 2020)
Overview
This entry on zhichai.net catalogs a 2020 Amazon Science publication: "Multi-objective ranking optimization for product search using stochastic label aggregation" (KDD 2020).
- Source: https://www.amazon.science/publications/multi-objective-ranking-optimization-for-product-search-using-stochastic-label-aggregation
- Section: Ranking for Search
- A unified, probabilistic view of combining heterogeneous supervision signals for ranking.
- A single-model serving path, reducing infrastructure and maintenance costs versus per-objective model ensembles.
- Applied to Amazon product search at scale, demonstrating that aggregated-objective training can match or approach per-objective baselines on their respective metrics.
- Multi-objective ranking as label aggregation offers a principled alternative to grid-searching loss weights.
- Stochastic sampling of objectives during training makes the trade-off tunable via sampling probabilities rather than retraining pipelines.
- Online constraints — latency, cost, and the gap between offline metrics and business KPIs — remain the hard limits on any ranking redesign.
- Quantitative results should be verified against the original PDF; this entry is based on public metadata and the publication abstract.
- Deep Learning to Rank in Industrial Search Engines
- Multi-Objective Recommendation in the Era of Generative AI: A Survey
- A Generative Re-ranking Model for List-level Multi-objective Optimization
- A Thorough Comparison of Cross-Encoders and LLMs for Reranking
- Adaptive Neural Ranking Framework: Toward Maximized Business Goal
- Original publication: *Multi-objective ranking optimization for product search using stochastic label aggregation*, Amazon Science / KDD 2020. See the link above for the official page and PDF.
Problem and Motivation
Industrial product search must balance multiple, often conflicting objectives — relevance, purchase likelihood, revenue contribution, and user experience. Typical approaches either train separate models per objective (costly to serve and tune) or combine objectives via hand-weighted losses (fragile and labor-intensive). The paper tackles the question of how to train a single ranker that optimizes several objectives jointly when their labels come from different, noisy sources (e.g., clicks, purchases, add-to-cart events).
Core Contribution
The authors propose stochastic label aggregation: the multi-objective learning problem is reformulated as a probabilistic label aggregation task. During training, target labels are stochastically sampled according to objective-specific priorities, so that a single ranking model internalizes the trade-off among objectives without requiring separate models or manual loss weighting. Key points: