The Posterior Winner Can Fail the Robust Requirement
Abstract
Constrained best-arm identification and robust ranking can disagree because admissibility and protected performance are distinct from nominal attraction. Evaluation should preserve both definitions and identify the uncertainty driving each observation. Independent final outcomes test the complete action. A budget-efficient nominal winner is incomplete evidence when feasibility under protected conditions limits use. This focused synthesis develops an empirical comparison that preserves the terminal action, observation process, and total verification cost. Its proposed tests are prospective; no new simulation run, model-training result, or intervention effect is reported.
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