Statistical Guarantees in the Search for Less Discriminatory Algorithms

ICLR 2026 Conference SubmissionAnonymous Authors
fairnessanytime-valid inferencesequential decision-making
Abstract:

Recent scholarship has argued that firms building data-driven decision systems in high-stakes domains like employment, credit, and housing should search for “less discriminatory algorithms” (LDAs) (Black et al., 2023). That is, for a given decision problem, firms considering deploying a model should make a good-faith effort to find equally performant models with lower disparate impact across social groups. Evidence from the literature on model multiplicity shows that randomness in training pipelines can lead to multiple models with the same performance, but meaningful variations in disparate impact. This suggests that developers can find LDAs simply by randomly retraining models. Firms cannot continue retraining forever, though, which raises the question: What constitutes a good-faith effort? In this paper, we formalize LDA search via model multiplicity as an optimal stopping problem, where a model developer with limited information wants to produce strong evidence that they have sufficiently explored the space of models. Our primary contribution is an adaptive stopping algorithm that yields a high-probability upper bound on the gains achievable from a continued search, allowing the developer to certify (e.g., to a court) that their search was sufficient. We provide a framework under which developers can impose stronger assumptions about the distribution of models, yielding correspondingly stronger bounds. We validate the method on real-world lending datasets.

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This report is AI-GENERATED using Large Language Models and WisPaper (A scholar search engine). It analyzes academic papers' tasks and contributions against retrieved prior work. While this system identifies POTENTIAL overlaps and novel directions, ITS COVERAGE IS NOT EXHAUSTIVE AND JUDGMENTS ARE APPROXIMATE. These results are intended to assist human reviewers and SHOULD NOT be relied upon as a definitive verdict on novelty.
NOTE that some papers exist in multiple, slightly different versions (e.g., with different titles or URLs). The system may retrieve several versions of the same underlying work. The current automated pipeline does not reliably align or distinguish these cases, so human reviewers will need to disambiguate them manually.
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Overview

Overall Novelty Assessment

The paper formalizes the search for less discriminatory algorithms as an optimal stopping problem, proposing an adaptive algorithm that provides high-probability upper bounds on achievable fairness gains from continued retraining. It resides in the Statistical Certification and Model Multiplicity Analysis leaf under Fairness Evaluation and Testing Methodologies, where it is currently the sole occupant. This placement reflects a relatively sparse research direction focused on formal verification of fairness properties across multiple model instantiations, contrasting with the more crowded intervention-focused branches like Fairness-Aware Training (15 papers across four leaves) and Data-Centric Bias Mitigation (4 papers across two leaves).

The taxonomy reveals that most fairness research concentrates on intervention techniques—adversarial training, reweighting strategies, and data augmentation—rather than post-hoc certification. The paper's neighboring branches include Adversarial and Automated Fairness Testing (1 paper) and Procedural and Explainability-Based Fairness Assessment (1 paper), both emphasizing empirical robustness checks rather than statistical guarantees. While Fairness-Aware Training branches develop methods to embed fairness constraints during learning, this work addresses the complementary question of certifying whether retraining efforts have sufficiently explored the model space, bridging evaluation methodologies with the retraining practices documented in adjacent intervention categories.

Among 17 candidates examined, the adaptive stopping algorithm contribution shows one refutable candidate among 10 examined, suggesting some overlap with prior work on stopping criteria or bound estimation. The formalization of LDA search as an optimal stopping problem (1 candidate examined, 0 refutable) and the distributional assumptions framework (6 candidates examined, 0 refutable) appear more distinctive within this limited search scope. The relatively small candidate pool reflects the sparse literature on statistical certification approaches compared to the broader fairness intervention landscape, though the single refutation for the stopping algorithm indicates that elements of the technical approach may have precedent in related optimization or sequential decision-making contexts.

Based on top-17 semantic matches, the work appears to occupy a genuinely underexplored niche at the intersection of model multiplicity analysis and fairness certification. The limited search scope means we cannot rule out relevant work in adjacent fields like sequential experimentation or multi-armed bandits that might inform the stopping problem formulation. The taxonomy structure suggests this certification perspective is less developed than intervention techniques, though the single sibling-less leaf position may partly reflect taxonomy granularity rather than absolute novelty.

Taxonomy

Core-task Taxonomy Papers
50
3
Claimed Contributions
17
Contribution Candidate Papers Compared
1
Refutable Paper

Research Landscape Overview

Core task: Searching for less discriminatory algorithms through model retraining. The field has evolved into a rich ecosystem organized around eight major branches. Bias Detection and Measurement Frameworks establish the diagnostic tools needed to quantify disparities, while Fairness-Aware Training and Retraining Interventions develop algorithmic techniques that embed fairness constraints directly into the learning process—works such as Balanced Training[6] and Individual Fairness Reweighting[10] exemplify this strand. Data-Centric Bias Mitigation tackles imbalances at the source through augmentation and sampling strategies (e.g., Data Augmentation Fairness[48]), whereas Post-Training Bias Correction and Model Adjustment offers lightweight remedies like Last Layer Retraining[46] that modify trained models without full retraining. Fairness Evaluation and Testing Methodologies provide rigorous certification and adversarial probing (Adversarial Fairness Testing[32]), and Domain-Specific Fairness Applications translate these methods into healthcare (Cardiovascular Risk Prediction[16], Chest XRay Bias[21]), finance (FinTech Debiasing[18]), and other sectors. Theoretical Foundations anchor the field in justice frameworks (Multilevel Justice Framework[11], Procedural Fairness[4]), while Specialized Technical Methods address auxiliary challenges such as federated learning fairness and unlearning. A particularly active line of inquiry examines how fairness properties can be certified or stress-tested after retraining, contrasting statistical guarantees with empirical robustness checks. Less Discriminatory Algorithms[0] sits within the Statistical Certification and Model Multiplicity Analysis cluster under Fairness Evaluation and Testing Methodologies, emphasizing formal verification of fairness across multiple model instantiations—a perspective that complements the more intervention-focused approaches in Mitigating Algorithmic Bias[1] and the unlearning strategies in Group Fairness Unlearning[2]. While many studies prioritize designing new training objectives or data preprocessing pipelines, this work zooms in on the post-hoc question of whether a retrained model reliably reduces discrimination across plausible parameter configurations. This certification angle bridges the gap between fairness-aware retraining techniques and the broader need for trustworthy deployment, offering a rigorous lens on model multiplicity that is less prominent in purely application-driven or data-centric branches.

Claimed Contributions

Formalization of LDA search as an optimal stopping problem

The authors formalize the search for less discriminatory algorithms as an optimal stopping problem. In this framework, a model developer seeks to determine when they have sufficiently explored the space of models by retraining, despite having limited information about the distribution of possible models.

1 retrieved paper
Adaptive stopping algorithm with high-probability upper bounds

The authors develop an adaptive stopping algorithm (Algorithm 1) and corresponding theorem (Theorem 3.5) that provides high-probability upper bounds on the marginal value of training additional models. This allows developers to certify to third parties that their search for less discriminatory algorithms was adequate.

10 retrieved papers
Can Refute
Framework for incorporating distributional assumptions to strengthen bounds

The authors provide a framework that allows developers to impose additional knowledge or assumptions about data and model distributions. Under these stronger assumptions, the framework yields correspondingly stronger upper bounds on the marginal value of continued model retraining.

6 retrieved papers

Core Task Comparisons

Comparisons with papers in the same taxonomy category

Within the taxonomy built over the current TopK core-task papers, the original paper is assigned to a leaf with no direct siblings and no cousin branches under the same grandparent topic. In this retrieved landscape, it appears structurally isolated, which is one partial signal of novelty, but still constrained by search coverage and taxonomy granularity.

Contribution Analysis

Detailed comparisons for each claimed contribution

Contribution

Formalization of LDA search as an optimal stopping problem

The authors formalize the search for less discriminatory algorithms as an optimal stopping problem. In this framework, a model developer seeks to determine when they have sufficiently explored the space of models by retraining, despite having limited information about the distribution of possible models.

Contribution

Adaptive stopping algorithm with high-probability upper bounds

The authors develop an adaptive stopping algorithm (Algorithm 1) and corresponding theorem (Theorem 3.5) that provides high-probability upper bounds on the marginal value of training additional models. This allows developers to certify to third parties that their search for less discriminatory algorithms was adequate.

Contribution

Framework for incorporating distributional assumptions to strengthen bounds

The authors provide a framework that allows developers to impose additional knowledge or assumptions about data and model distributions. Under these stronger assumptions, the framework yields correspondingly stronger upper bounds on the marginal value of continued model retraining.