Optimal Decision Rules for Composite Binary Hypothesis Testing under Neyman-Pearson Framework
Yanglei Song, Berkan Dulek, Sinan Gezici
TL;DR
This work analyzes non-asymptotic composite binary hypothesis testing under the Neyman-Pearson framework with nonlinear objectives on detection probability. It shows that every achievable power function can be realized by a generalized Bayes rule, enabling single-threshold or threshold-with-randomization decision rules based on integrated likelihood ratios. The authors derive integrated and supremum false-alarm controls for composite nulls and alternatives, including clean exponential-family specializations and numerical demonstrations for Normal and Binomial models. The results hinge on reducing optimal rules to a threshold on a function H(y) of the data, with least-favorable-distribution arguments underpinning worst-case analyses. The framework supports nonlinear utility-inspired objectives and robust performance criteria, with practical implications for behavioral-utility detection and robust hypothesis testing.
Abstract
The composite binary hypothesis testing problem within the Neyman-Pearson framework is considered. The goal is to maximize the expectation of a nonlinear function of the detection probability, integrated with respect to a given probability measure, subject to a false-alarm constraint. It is shown that each power function can be realized by a generalized Bayes rule that maximizes an integrated rejection probability with respect to a finite signed measure. For a simple null hypothesis and a composite alternative, optimal single-threshold decision rules based on an appropriately weighted likelihood ratio are derived. The analysis is extended to composite null hypotheses, including both average and worst-case false-alarm constraints, resulting in modified optimal threshold rules. Special cases involving exponential family distributions and numerical examples are provided to illustrate the theoretical results.
