Labels or Preferences? Budget-Constrained Learning with Human Judgments over AI-Generated Outputs
Zihan Dong, Ruijia Wu, Linjun Zhang
TL;DR
This work tackles budget-constrained learning where ground-truth labels, pairwise human preferences, and AI-generated pseudo-labels are combined to estimate a target parameter θ(P_{X,Y}). It casts budget allocation as a semiparametric, monotone missing-data problem under MAR and develops PCAL, an EIF-based method that jointly learns an optimal multi-type labeling policy α_j and constructs a statistically efficient estimator of θ. Theoretical results establish asymptotic normality and the semiparametric efficiency bound for PCAL, along with robustness guarantees to nuisance-model misspecification; a covariate-agnostic variant (MCAR) is also developed. Empirical evaluations on linear regression and a politeness analysis demonstrate substantial reductions in CI length while preserving coverage, validating practical efficiency gains under budget constraints. Overall, PCAL provides a principled, variance-minimizing framework for budget-aware data acquisition in modern AI systems.
Abstract
The increasing reliance on human preference feedback to judge AI-generated pseudo labels has created a pressing need for principled, budget-conscious data acquisition strategies. We address the crucial question of how to optimally allocate a fixed annotation budget between ground-truth labels and pairwise preferences in AI. Our solution, grounded in semi-parametric inference, casts the budget allocation problem as a monotone missing data framework. Building on this formulation, we introduce Preference-Calibrated Active Learning (PCAL), a novel method that learns the optimal data acquisition strategy and develops a statistically efficient estimator for functionals of the data distribution. Theoretically, we prove the asymptotic optimality of our PCAL estimator and establish a key robustness guarantee that ensures robust performance even with poorly estimated nuisance models. Our flexible framework applies to a general class of problems, by directly optimizing the estimator's variance instead of requiring a closed-form solution. This work provides a principled and statistically efficient approach for budget-constrained learning in modern AI. Simulations and real-data analysis demonstrate the practical benefits and superior performance of our proposed method.
