Learning to Recommend with Multiple Cascading Behaviors

TL;DR

This paper introduces NMTR, a neural multi-task learning model that effectively leverages multiple user behaviors and their cascading relationships to improve recommendation quality, especially for sparse users.

Contribution

The paper proposes a novel neural multi-task recommendation model that captures multi-type behavior interactions and cascading effects, outperforming existing single-behavior and multi-behavior models.

Findings

NMTR significantly outperforms state-of-the-art recommenders.

Modeling multiple behaviors benefits sparse user recommendations.

Joint multi-task learning effectively exploits behavior signals.

Abstract

Most existing recommender systems leverage user behavior data of one type only, such as the purchase behavior in E-commerce that is directly related to the business KPI (Key Performance Indicator) of conversion rate. Besides the key behavioral data, we argue that other forms of user behaviors also provide valuable signal, such as views, clicks, adding a product to shop carts and so on. They should be taken into account properly to provide quality recommendation for users. In this work, we contribute a new solution named NMTR (short for Neural Multi-Task Recommendation) for learning recommender systems from user multi-behavior data. We develop a neural network model to capture the complicated and multi-type interactions between users and items. In particular, our model accounts for the cascading relationship among different types of behaviors (e.g., a user must click on a product before purchasing it). To fully exploit the signal in the data of multiple types of behaviors, we perform a joint optimization based on the multi-task learning framework, where the optimization on a behavior is treated as a task. Extensive experiments on two real-world datasets demonstrate that NMTR significantly outperforms state-of-the-art recommender systems that are designed to learn from both single-behavior data and multi-behavior data. Further analysis shows that modeling multiple behaviors is particularly useful for providing recommendation for sparse users that have very few interactions.