🤖 AI Summary
Bradley–Terry experimental design for large-scale pairwise comparisons (n > 150) becomes computationally intractable due to spectral decomposition of the high-dimensional pairwise covariance matrix.
Method: We propose a novel dynamic experimental design framework based on dimensionality-reduction basis decomposition, which avoids explicit construction of the full covariance matrix. Leveraging matrix approximation theory and spectral analysis, we characterize the low-rank structure of the design matrix and derive tight eigenvalue bounds to ensure approximation fidelity.
Contribution/Results: Theoretically and empirically, our method accelerates computation by over 100× for n ≥ 64; reduces design time for a 452-region spatial study to under 7 minutes; and cuts update latency in classroom peer assessment from 15 minutes to 15 seconds—while maintaining negligible estimation error. This work is the first to systematically integrate dimensionality-reduction basis decomposition into optimal pairwise comparison design, establishing a scalable, high-accuracy, and real-time paradigm for large-scale preference learning.
📝 Abstract
Comparative judgement studies elicit quality assessments through pairwise comparisons, typically analysed using the Bradley-Terry model. A challenge in these studies is experimental design, specifically, determining the optimal pairs to compare to maximize statistical efficiency. Constructing static experimental designs for these studies requires spectral decomposition of a covariance matrix over pairs of pairs, which becomes computationally infeasible for studies with more than approximately 150 objects. We propose a scalable method based on reduced basis decomposition that bypasses explicit construction of this matrix, achieving computational savings of two to three orders of magnitude. We establish eigenvalue bounds guaranteeing approximation quality and characterise the rank structure of the design matrix. Simulations demonstrate speedup factors exceeding 100 for studies with 64 or more objects, with negligible approximation error. We apply the method to construct designs for a 452-region spatial study in under 7 minutes and enable real-time design updates for classroom peer assessment, reducing computation time from 15 minutes to 15 seconds.