ORTHOGONAL PERMUTATION SAMPLING FOR SHAPLEY VALUES: UNBIASED STRATIFIED ESTIMATORS WITH VARIANCE GUARANTEES

Authors

  • YASH VARSHNEY GURUKUL THE SCHOOL, INDIA https://orcid.org/0009-0007-7563-0567
  • RANAV TYAGI GURUKUL THE SCHOOL
  • ANURAG SINHA COMPUTER SCIENCE DEPARTMENT, ICFAI UNIVERSITY

DOI:

https://doi.org/10.64680/jisads.v3i2.44

Abstract

Shapley values for feature attribution suffer from high variance requiring thousands of model evaluations. We introduce Orthogonal Permutation Sampling (OPS), achieving provable variance reduction through: (i) exact position stratification, (ii) antithetic permutation coupling, and (iii) control variates. We prove finite-sample variance dominance over Monte Carlo and non-positive covariance under submodularity. Empirical validation across six benchmarks shows 5-26× variance reduction for typical dimensions (n=10-20) and 67× for n=50. OPS achieves 2-5× lower MSE than KernelSHAP at equivalent budgets with 7% runtime overhead (all p<0.001). The framework is model-agnostic, maintains exact unbiasedness, scales linearly to n=100, and provides production-ready reliable feature attributions.

Published

2026-01-11