Heterogeneous Data Game: Characterizing the Model Competition Across Multiple Data Sources
Renzhe Xu, Kang Wang, Bo Li
TL;DR
The paper introduces the Heterogeneous Data Game (HD-Game), a game-theoretic framework for analyzing competition among multiple ML model providers across heterogeneous data sources. It defines a Mahalanobis-distance-based loss and two data-source choice models (Proximity and Probability with temperature $t$) to study Pure Nash Equilibria under monopoly, duopoly, and multi-provider settings. The authors derive conditions for the existence of homogeneous and heterogeneous PNE, showing that heterogeneity is common under proximity when dominant data sources exist, while temperature in the probability model can toggle between homogeneous and heterogeneous equilibria and even allow coexistence. Synthetic experiments elucidate how data-heterogeneity magnitude and $t$ influence equilibrium structure, providing insights for policy design aimed at fostering diverse, fair model offerings in competitive ML marketplaces. Overall, the HD-Game framework links distribution shifts, market structure, and strategic model deployment to offer principled guidance for regulators and practitioners.
Abstract
Data heterogeneity across multiple sources is common in real-world machine learning (ML) settings. Although many methods focus on enabling a single model to handle diverse data, real-world markets often comprise multiple competing ML providers. In this paper, we propose a game-theoretic framework -- the Heterogeneous Data Game -- to analyze how such providers compete across heterogeneous data sources. We investigate the resulting pure Nash equilibria (PNE), showing that they can be non-existent, homogeneous (all providers converge on the same model), or heterogeneous (providers specialize in distinct data sources). Our analysis spans monopolistic, duopolistic, and more general markets, illustrating how factors such as the "temperature" of data-source choice models and the dominance of certain data sources shape equilibrium outcomes. We offer theoretical insights into both homogeneous and heterogeneous PNEs, guiding regulatory policies and practical strategies for competitive ML marketplaces.
