Scalable and Interpretable Representation Alignment with Ordinal Similarity

arXiv:2606.16379 · cs.LG, stat.ML · Submitted 2026-06-15 · Read on arXiv

Diogo Soares, Pankhil Gawade, Andrea Dittadi, Ewa Szczurek

cs.LG, stat.ML

Submitted: 2026-06-15

Code: https://github.com/diogosoares22/ordinal-similarity-metrics

License: http://creativecommons.org/licenses/by/4.0/

The gist: Evaluating representation similarity is fundamental to representation learning.

Terminology

Abstract

Evaluating representation similarity is fundamental to representation learning. However, existing metrics suffer from significant limitations: they lack interpretability due to shifting baselines, lack robustness to outliers, and are computationally intractable for large datasets, forcing reliance on heuristic approximations. To address this, we develop an ordinal-similarity framework, instantiated by the Triplet (TSI) and Quadruplet (QSI) Similarity Indices, which measure alignment by quantifying the consistency of ordinal relationships. We theoretically demonstrate this formulation is inherently interpretable, robust to outliers, and computationally efficient. Finally, we establish a formal equivalence between TSI and local neighborhood alignment, measured by Mutual Nearest Neighbors. Empirically, we validate these properties and show that ordinal similarity offers a scalable approach to measuring alignment, enabling practitioners to better understand and design representations.

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