DCEO: Direct Causal Effect Optimization for Long-Term User Value Modeling in E-commerce Search
Organizations: Taobao & Tmall Group of Alibaba Hangzhou, Zhejiang, China · Taobao & Tmall Group of Alibaba Beijing, China
Abstract
Industrial e-commerce search systems ultimately aim to optimize the user-level long-term objective, such as n-day cumulative purchases or gross merchandise value (GMV) per user. However, such objectives are defined at the user level, whereas search ranking is based on item-level scores within each request. Existing methods typically bridge this granularity gap through manually designed multi-objective fusion, where predictions of multiple item-level objectives, such as clicks, carts, purchases, and transaction value, are combined into a ranking score that serves as a proxy for the ultimate objective. Such hand-crafted fusion schemes rely on a small set of manually tuned weights, limiting fine-grained personalization and leading to suboptimal alignment with the ultimate objective. In this paper, we propose DCEO (Direct Causal Effect Optimization), a data-driven framework for learning item-level proxy scores that are better aligned with the ultimate objective. We first aggregate the item-level proxy scores into a user-level proxy metric and quantify its alignment with the ultimate objective using a relative causal effect. We then develop an actor-critic framework, where the critic estimates the ultimate objective for a given user-level proxy metric, and the actor dynamically generates context-dependent fusion weights over multiple objectives to construct the item-level proxy scores and is trained to directly optimize the relative causal effect. Extensive offline experiments and analyses demonstrate the effectiveness and interpretability of DCEO. In addition, DCEO has been deployed in a large-scale industrial e-commerce search system, outperforming the conventional GMV proxy by 0.36% in GMV in a 41-day online A/B test.
Figures & tables
| Score name | Meaning |
|---|---|
| impr2click | Probability of a click after an impression. |
| impr2cart | Probability of a cart addition after an impression. |
| impr2pay | Probability of a purchase after an impression. |
| impr2gmv | GMV generated after an impression. |
| impr2pay10 | Probability of a purchase with transaction value above 10 after an impression. |
| impr2pay30 | Probability of a purchase with transaction value above 30 after an impression. |
| Statistic | impr2click | impr2pay | click2pay10 | click2pay30 | click2pay100 | click2pay1000 |
|---|---|---|---|---|---|---|
| Mean | 0.404 | 0.032 | 0.154 | 0.079 | 0.105 | 0.205 |
| Standard deviation | 0.115 | 0.096 | 0.057 | 0.046 | 0.049 | 0.067 |
| Actor loss | RCE |
|---|---|
| Predictive association optimization: | 0.022 |
| Causal effect optimization: | 0.031 |
| Causal effect optimization: | 0.053 |
| Actor loss | RCE |
|---|---|
| 0.031 | |
| 0.048 | |
| 0.052 | |
| 0.053 | |
| 0.047 |
| Predicted-score set | RCE |
|---|---|
| impr2gmv only | 0.027 |
| Basic impression-level set | 0.039 |
| Value-aware set | 0.041 |
| Conversion-funnel set | 0.040 |
| Full 17-score set | 0.053 |
| Ultimate objective | impr2click | click2pay | click2pay10 | click2pay30 | click2pay100 | click2pay1000 |
|---|---|---|---|---|---|---|
| 4-day click count | 0.999 | 0.000 | 0.000 | 0.000 | 0.000 | 0.000 |
| 4-day purchase count | 0.531 | 0.101 | 0.256 | 0.000 | 0.000 | 0.000 |
| 4-day GMV | 0.404 | 0.032 | 0.154 | 0.079 | 0.105 | 0.205 |
| 4-day purchase count GMV | 0.407 | 0.000 | 0.056 | 0.098 | 0.103 | 0.187 |
| Ultimate objective | impr2click | click2pay | click2pay10 | click2pay30 | click2pay100 | click2pay1000 |
|---|---|---|---|---|---|---|
| 1-day GMV | 0.331 | 0.034 | 0.108 | 0.144 | 0.127 | 0.158 |
| 2-day GMV | 0.379 | 0.000 | 0.000 | 0.140 | 0.129 | 0.189 |
| 3-day GMV | 0.417 | 0.000 | 0.155 | 0.081 | 0.122 | 0.202 |
| 4-day GMV | 0.404 | 0.032 | 0.154 | 0.079 | 0.105 | 0.205 |
| Metric | Relative change |
|---|---|
| Click count | |
| Purchase count | |
| GMV |
E-Commerce Search
E-commerce search studies how to match shoppers’ queries, preferences, and product signals with useful items in online marketplaces.
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