Paper Overview
Field: Machine Learning Authors: Sho Kawano, Zehang Richard Li, Paul A. Parker Published: 2026-09-17 arXiv: 2609.20758
Summary
Evaluating an AI system requires disaggregated assessment, as performance varies across domains such as benchmark task types or conversation types in deployed agents. Exhaustive testing is expensive, so evaluation rests on a sample of labeled units. The authors treat the evaluation set as a finite population and seek accurate point and interval estimates of each domain mean. Direct estimators, including prediction-powered inference (PPI), use only a domain's own labels and are imprecise where labels are few.
Small area estimation addresses this problem, and the authors build on it to develop an integrated workflow for estimation and validation:
- Estimation: They propose prediction-powered smoothing (PP-S), a Bayesian model fit to each domain's prediction-powered estimate, with an extension (PP-TS) that borrows information across reporting taxonomies.
- Validation: They derive a new approximately unbiased design-based cross-validation score for selecting between direct and smoothed estimators.
- The proposed estimators outperform direct estimators in both point and interval estimates, with coverage close to nominal levels.
- At the same sampling budget, their selection score performs comparably to an independent validation set and estimates the error of the chosen estimator much more accurately.
Experiments and Results
The methods are studied on curated benchmarks with verifiable scores and on deployed agent traffic with human ratings—in both cases with every outcome fully observed. Results show that:
Original Abstract
> Evaluating an AI system requires disaggregated assessment, as performance varies across domains such as benchmark task types or conversation types in deployed agents. Exhaustive testing is expensive, so evaluation rests on a sample of labeled units. We treat the evaluation set as a finite population and seek accurate point and interval estimates of each domain mean. Direct estimators, including prediction-powered inference (PPI), use only a domain's own labels and are imprecise where labels are few. Small area estimation addresses this problem, and we build on it to develop an integrated workflow for estimation and validation. For estimation, we propose prediction-powered smoothing (PP-S), a Bayesian model fit to each domain's prediction-powered estimate, with an extension that borrows str...
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