🤖 AI Summary
This paper addresses the problem of model-free inference of global rankings from noisy pairwise comparisons (e.g., tennis match outcomes), where both the latent object strengths and the functional mapping from strengths to win probabilities are unknown. To overcome the limitations of parametric models—such as Bradley–Terry—which impose strong prior assumptions on the link function (e.g., logistic), we propose the first Bayesian nonparametric framework that jointly infers latent strength parameters and an unknown response function. Our method integrates variational adaptive function modeling with MCMC sampling and incorporates empirical calibration to enhance robustness. Evaluated on real-world datasets spanning sports and academic citation networks, our approach significantly outperforms baselines relying on prespecified link functions, demonstrating superior ranking accuracy and generalization stability even under model misspecification.
📝 Abstract
We consider the problem of ranking objects from noisy pairwise comparisons, for example, ranking tennis players from the outcomes of matches. We follow a standard approach to this problem and assume that each object has an unobserved strength and that the outcome of each comparison depends probabilistically on the strengths of the comparands. However, we do not assume to know a priori how skills affect outcomes. Instead, we present an efficient algorithm for simultaneously inferring both the unobserved strengths and the function that maps strengths to probabilities. Despite this problem being under-constrained, we present experimental evidence that the conclusions of our Bayesian approach are robust to different model specifications. We include several case studies to exemplify the method on real-world data sets.