PhAIL: A Real-Robot VLA Benchmark and Distributional Methodology
Abstract
Real-world evaluation of vision-language-action (VLA) policies still rests on binary success rate at a fixed timeout with rollouts per condition, almost always without confidence intervals or paired statistical comparison; these cohort sizes struggle to resolve close comparisons reliably. We introduce PhAIL (Physical AI Leaderboard, https://phail.ai), an open real-robot benchmark on a Franka FR3 (dataset, per-rollout artifacts, and end-to-end reference implementation) of a distributional evaluation methodology: the time-to-success cumulative distribution function (CDF) as the evaluation primitive, with two separated jobs. The first is scoring via Human-Relative Throughput (HRT), a dimensionless scalar with bootstrap confidence intervals, anchored to same-fixture human teleoperation. The second is a significance test (Kolmogorov-Smirnov, computed per-object and macro-averaged across objects). On four publicly-available VLAs, the macro-averaged KS test resolves two close comparisons (GR00T vs. ACT, OpenPI vs. ACT) at rollouts per (model, object) cell where binary-threshold metrics do not; the closest pair (OpenPI vs. GR00T) remains unresolved within our budget. The best evaluated VLA is slower per operation (RMST ratio) than the human reference.
Comments: 22 pages, 10 figures, 8 tables. Dataset, analysis pipeline, and paper source: https://phail.ai and https://github.com/Positronic-Robotics/phail-paper
Cite
@article{arxiv.2605.29710,
title = {PhAIL: A Real-Robot VLA Benchmark and Distributional Methodology},
author = {Sergey Arkhangelskiy},
journal= {arXiv preprint arXiv:2605.29710},
year = {2026}
}