Predicting Preference Flips in Commerce Search

TL;DR

This paper introduces the Random Shopper Model, a new ranking approach that accounts for preference flips influenced by context, outperforming traditional scoring methods in commerce search scenarios.

Contribution

The paper proposes the Random Shopper Model, a novel ranking framework that models context-dependent preferences using Markov chains, and provides an efficient learning algorithm.

Findings

The model captures preference flips based on context.

It outperforms traditional scoring-based ranking methods.

Experimental results demonstrate improved accuracy in commerce search.

Abstract

Traditional approaches to ranking in web search follow the paradigm of rank-by-score: a learned function gives each query-URL combination an absolute score and URLs are ranked according to this score. This paradigm ensures that if the score of one URL is better than another then one will always be ranked higher than the other. Scoring contradicts prior work in behavioral economics that showed that users' preferences between two items depend not only on the items but also on the presented alternatives. Thus, for the same query, users' preference between items A and B depends on the presence/absence of item C. We propose a new model of ranking, the Random Shopper Model, that allows and explains such behavior. In this model, each feature is viewed as a Markov chain over the items to be ranked, and the goal is to find a weighting of the features that best reflects their importance. We show that our model can be learned under the empirical risk minimization framework, and give an efficient learning algorithm. Experiments on commerce search logs demonstrate that our algorithm outperforms scoring-based approaches including regression and listwise ranking.