Fair and Optimal Classification via Post-Processing
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Abstract (arXiv)
To mitigate the bias exhibited by machine learning models, fairness criteria can be integrated into the training process to ensure fair treatment across all demographics, but it often comes at the expense of model performance. Understanding such tradeoffs, therefore, underlies the design of fair algorithms. To this end, this paper provides a complete characterization of the inherent tradeoff of demographic parity on classification problems, under the most general multi-group, multi-class, and noisy setting. Specifically, we show that the minimum error rate achievable by randomized and attribute-aware fair classifiers is given by the optimal value of a Wasserstein-barycenter problem. On the practical side, our findings lead to a simple post-processing algorithm that derives fair classifiers from score functions, which yields the optimal fair classifier when the score is Bayes optimal. We provide suboptimality analysis and sample complexity for our algorithm, and demonstrate its effectiveness on benchmark datasets.
Key facts. Cited by 50 papers in the map (data through 7 Oct 2026). Builds on 40 of its 89 references that are in the map. First posted on arXiv 3 Nov 2022.
Builds on
40 of 89 references.
References · 40
- 2018BERT: Pre-training of Deep Bidirectional Transformers for Language Understandingcited by 40,204
- 2017On Calibration of Modern Neural Networkscited by 4,860
- 2016Equality of Opportunity in Supervised Learningcited by 2,000
- 2016Man is to Computer Programmer as Woman is to Homemaker? Debiasing Word Embeddingscited by 1,304
- 2016Fair prediction with disparate impact: A study of bias in recidivism prediction instrumentscited by 671
- 2018Gender Bias in Coreference Resolution: Evaluation and Debiasing Methodscited by 657
- 2016CVXPY: A Python-Embedded Modeling Language for Convex Optimizationcited by 633
- 2016Inherent Trade-Offs in the Fair Determination of Risk Scorescited by 582
- 2021Retiring Adult: New Datasets for Fair Machine Learningcited by 443
- 2020Null It Out: Guarding Protected Attributes by Iterative Nullspace Projectioncited by 442
- 2017On Fairness and Calibrationcited by 406
- 2017Algorithmic decision making and the cost of fairnesscited by 402
28 more
- 2017Preventing Fairness Gerrymandering: Auditing and Learning for Subgroup Fairnesscited by 381
- 2021Persistent Anti-Muslim Bias in Large Language Modelscited by 376
- 2020Fairness in Machine Learning: A Surveycited by 369
- 2018Learning Adversarially Fair and Transferable Representationscited by 353
- 2019Bias in Bios: A Case Study of Semantic Representation Bias in a High-Stakes Settingcited by 346
- 2017Fairness in Criminal Justice Risk Assessments: The State of the Artcited by 315
- 2016Stochastic Optimization for Large-scale Optimal Transportcited by 188
- 2018Fair Clustering Through Fairletscited by 176
- 2019Fair Regression: Quantitative Definitions and Reduction-based Algorithmscited by 168
- 2016Fairness in Learning: Classic and Contextual Banditscited by 167
- 2019Inherent Tradeoffs in Learning Fair Representationscited by 144
- 2019Wasserstein Fair Classificationcited by 131
- 2017FA*IR: A Fair Top-k Ranking Algorithmcited by 113
- 2020Fair Regression with Wasserstein Barycenterscited by 99
- 2018Learning Controllable Fair Representationscited by 83
- 2019Scalable Fair Clusteringcited by 78
- 2019Conditional Learning of Fair Representationscited by 78
- 2016A Confidence-Based Approach for Balancing Fairness and Accuracycited by 73
- 2018Online Learning with an Unknown Fairness Metriccited by 61
- 2019Leveraging Labeled and Unlabeled Data for Consistent Fair Binary Classificationcited by 60
- 2019Average Individual Fairness: Algorithms, Generalization and Experimentscited by 46
- 2022Bayes-Optimal Classifiers under Group Fairnesscited by 24
- 2022Fair learning with Wasserstein barycenters for non-decomposable performance measurescited by 24
- 2016Fair Algorithms for Infinite and Contextual Banditscited by 16
- 2022Fair Bayes-Optimal Classifiers Under Predictive Paritycited by 16
- 2017Parallel Streaming Wasserstein Barycenterscited by 14
- 2019A gradual, semi-discrete approach to generative network training via explicit Wasserstein minimizationcited by 12
- 2021Towards Return Parity in Markov Decision Processescited by 12
Built on by
Citing papers per year: 2023: 7; 2024: 15; 2025: 17; 2026: 11.
50 papers.
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- 2023Revisiting Scalarization in Multi-Task Learning: A Theoretical Perspectivecited by 51
- 2024Representation Surgery: Theory and Practice of Affine Steeringcited by 47
- 2023FFB: A Fair Fairness Benchmark for In-Processing Group Fairness Methodscited by 33
- 2023FRAPPE: A Group Fairness Framework for Post-Processing Everythingcited by 16
- 2023Post-hoc Bias Scoring Is Optimal For Fair Classificationcited by 14
- 2024LibMOON: A Gradient-based MultiObjective OptimizatioN Library in PyTorchcited by 10
- 2024Counterfactual Fairness by Combining Factual and Counterfactual Predictionscited by 8
- 2024Differentially Private Post-Processing for Fair Regressioncited by 5
- 2024A Unifying Post-Processing Framework for Multi-Objective Learn-to-Defer Problemscited by 5
- 2024Post-Fair Federated Learning: Achieving Group and Community Fairness in Federated Learning via Post-processingcited by 4
- 2024Inducing Group Fairness in Prompt-Based Language Model Decisionscited by 3
- 2025Fairness-Aware Grouping for Continuous Sensitive Variables: Application for Debiasing Face Analysis with respect to Skin Tonecited by 3
38 more
- 2023Fair Supervised Learning with A Simple Random Sampler of Sensitive Attributescited by 2
- 2024Multi-Output Distributional Fairness via Post-Processingcited by 2
- 2024Demographic parity in regression and classification within the unawareness frameworkcited by 2
- 2024Efficient Fairness-Performance Pareto Front Computationcited by 2
- 2025The Cost of Local and Global Fairness in Federated Learningcited by 2
- 2025Enforcing Fair Predicted Scores on Intervals of Percentiles by Difference-of-Convex Constraintscited by 2
- 2025Meta Optimality for Demographic Parity Constrained Regression via Post-Processingcited by 2
- 2025FairAgent: Democratizing Fairness-Aware Machine Learning with LLM-Powered Agentscited by 2
- 2025Breaking the Dyadic Barrier: Rethinking Fairness in Link Prediction Beyond Demographic Paritycited by 2
- 2024UMOEA/D: A Multiobjective Evolutionary Algorithm for Uniform Pareto Objectives based on Decompositioncited by 1
- 2024OTTER: Effortless Label Distribution Adaptation of Zero-shot Modelscited by 1
- 2024AdapFair: Ensuring Adaptive Fairness for Machine Learning Operationscited by 1
- 2025Learning Pareto manifolds in high dimensions: How can regularization help?cited by 1
- 2025LoGoFair: Post-Processing for Local and Global Fairness in Federated Learningcited by 1
- 2025Bayes-Optimal Fair Classification with Multiple Sensitive Featurescited by 1
- 2025FairNet: Dynamic Fairness Correction without Performance Loss via Contrastive Conditional LoRAcited by 1
- 2025Randomized multi-class classification under system constraints: a unified approach via post-processingcited by 1
- 2026Optimal Fair Aggregation of Crowdsourced Noisy Labels using Demographic Parity Constraintscited by 1
- 2023An Empirical Study of Self-supervised Learning with Wasserstein Distancecited by 0
- 2023Constrained Reweighting of Distributions: an Optimal Transport Approachcited by 0
- 2024Fair Class-Incremental Learning using Sample Weightingcited by 0
- 2024Debiasify: Self-Distillation for Unsupervised Bias Mitigationcited by 0
- 2025A Critical Review of Predominant Bias in Neural Networkscited by 0
- 2025FedFACT: A Provable Framework for Controllable Group-Fairness Calibration in Federated Learningcited by 0
- 2025FairPOT: Balancing AUC Performance and Fairness with Proportional Optimal Transportcited by 0
- 2025FairAD: Computationally Efficient Fair Graph Clustering via Algebraic Distancecited by 0
- 2025Toward Unifying Group Fairness Evaluation from a Sparsity Perspectivecited by 0
- 2025Metanetworks as Regulatory Operators: Learning to Edit for Requirement Compliancecited by 0
- 2026Optimal Transport under Group Fairness Constraintscited by 0
- 2026Task-tailored Pre-processing: Fair Downstream Supervised Learningcited by 0
- 2026Operationalizing Fairness: Post-Hoc Threshold Optimization Under Hard Resource Limitscited by 0
- 2026Ethical Fairness in Ubiquitous Health Sensing without Known Attributescited by 0
- 2026A Model Ensemble-Based Post-Processing Framework for Fairness-Aware Predictioncited by 0
- 2026Demystifying the Optimal Fair Classifier in Multi-Class Classificationcited by 0
- 2026Fair Classification with Efficient and Post-hoc Controllable Fairness-Accuracy Trade-offcited by 0
- 2026Interpretable and Fair Generalized Additive Neural Networks via Multi-objective Learningcited by 0
- 2026A Comprehensive View of Fairness through Distributional Stabilitycited by 0
- 2026Sensitive-Topic Leakage Through LLM Routing Metadata: Measurement and Mitigationcited by 0
- 2026Sensitive-Topic Leakage Through LLM Routing Metadata: Measurement and Mitigation7 Oct 2026
- 2026A Comprehensive View of Fairness through Distributional Stability29 Sep 2026
- 2026Interpretable and Fair Generalized Additive Neural Networks via Multi-objective Learning5 Sep 2026
- 2026Fair Classification with Efficient and Post-hoc Controllable Fairness-Accuracy Trade-off26 Jun 2026
- 2026Demystifying the Optimal Fair Classifier in Multi-Class Classification30 May 2026
- 2026A Model Ensemble-Based Post-Processing Framework for Fairness-Aware Prediction19 Mar 2026
- 2026Ethical Fairness in Ubiquitous Health Sensing without Known Attributes10 Mar 2026
- 2026Operationalizing Fairness: Post-Hoc Threshold Optimization Under Hard Resource Limits26 Feb 2026
- 2026Optimal Fair Aggregation of Crowdsourced Noisy Labels using Demographic Parity Constraints30 Jan 2026
- 2026Task-tailored Pre-processing: Fair Downstream Supervised Learning17 Jan 2026
- 2026Optimal Transport under Group Fairness Constraints12 Jan 2026
- 2025Metanetworks as Regulatory Operators: Learning to Edit for Requirement Compliance17 Dec 2025
38 more
- 2025Randomized multi-class classification under system constraints: a unified approach via post-processing16 Dec 2025
- 2025Breaking the Dyadic Barrier: Rethinking Fairness in Link Prediction Beyond Demographic Parity9 Nov 2025
- 2025Toward Unifying Group Fairness Evaluation from a Sparsity Perspective1 Nov 2025
- 2025FairAD: Computationally Efficient Fair Graph Clustering via Algebraic Distance31 Oct 2025
- 2025FairNet: Dynamic Fairness Correction without Performance Loss via Contrastive Conditional LoRA22 Oct 2025
- 2025FairAgent: Democratizing Fairness-Aware Machine Learning with LLM-Powered Agents5 Oct 2025
- 2025FairPOT: Balancing AUC Performance and Fairness with Proportional Optimal Transport5 Aug 2025
- 2025Fairness-Aware Grouping for Continuous Sensitive Variables: Application for Debiasing Face Analysis with respect to Skin Tone15 Jul 2025
- 2025Meta Optimality for Demographic Parity Constrained Regression via Post-Processing16 Jun 2025
- 2025FedFACT: A Provable Framework for Controllable Group-Fairness Calibration in Federated Learning4 Jun 2025
- 2025Enforcing Fair Predicted Scores on Intervals of Percentiles by Difference-of-Convex Constraints18 May 2025
- 2025Bayes-Optimal Fair Classification with Multiple Sensitive Features1 May 2025
- 2025The Cost of Local and Global Fairness in Federated Learning27 Mar 2025
- 2025LoGoFair: Post-Processing for Local and Global Fairness in Federated Learning21 Mar 2025
- 2025Learning Pareto manifolds in high dimensions: How can regularization help?11 Mar 2025
- 2025A Critical Review of Predominant Bias in Neural Networks16 Feb 2025
- 2024Debiasify: Self-Distillation for Unsupervised Bias Mitigation1 Nov 2024
- 2024Fair Class-Incremental Learning using Sample Weighting2 Oct 2024
- 2024Efficient Fairness-Performance Pareto Front Computation26 Sep 2024
- 2024AdapFair: Ensuring Adaptive Fairness for Machine Learning Operations23 Sep 2024
- 2024LibMOON: A Gradient-based MultiObjective OptimizatioN Library in PyTorch4 Sep 2024
- 2024Demographic parity in regression and classification within the unawareness framework4 Sep 2024
- 2024Counterfactual Fairness by Combining Factual and Counterfactual Predictions3 Sep 2024
- 2024Multi-Output Distributional Fairness via Post-Processing31 Aug 2024
- 2024A Unifying Post-Processing Framework for Multi-Objective Learn-to-Defer Problems17 Jul 2024
- 2024Inducing Group Fairness in Prompt-Based Language Model Decisions24 Jun 2024
- 2024Post-Fair Federated Learning: Achieving Group and Community Fairness in Federated Learning via Post-processing28 May 2024
- 2024Differentially Private Post-Processing for Fair Regression7 May 2024
- 2024OTTER: Effortless Label Distribution Adaptation of Zero-shot Models12 Apr 2024
- 2024Representation Surgery: Theory and Practice of Affine Steering15 Feb 2024
- 2024UMOEA/D: A Multiobjective Evolutionary Algorithm for Uniform Pareto Objectives based on Decomposition14 Feb 2024
- 2023FRAPPE: A Group Fairness Framework for Post-Processing Everything5 Dec 2023
- 2023Fair Supervised Learning with A Simple Random Sampler of Sensitive Attributes10 Nov 2023
- 2023Constrained Reweighting of Distributions: an Optimal Transport Approach19 Oct 2023
- 2023An Empirical Study of Self-supervised Learning with Wasserstein Distance16 Oct 2023
- 2023Post-hoc Bias Scoring Is Optimal For Fair Classification9 Oct 2023
- 2023Revisiting Scalarization in Multi-Task Learning: A Theoretical Perspective27 Aug 2023
- 2023FFB: A Fair Fairness Benchmark for In-Processing Group Fairness Methods15 Jun 2023
- 2023Revisiting Scalarization in Multi-Task Learning: A Theoretical Perspectivecited by 51
- 2024Representation Surgery: Theory and Practice of Affine Steeringcited by 47
- 2023FFB: A Fair Fairness Benchmark for In-Processing Group Fairness Methodscited by 33
- 2023FRAPPE: A Group Fairness Framework for Post-Processing Everythingcited by 16
- 2023Post-hoc Bias Scoring Is Optimal For Fair Classificationcited by 14
- 2024LibMOON: A Gradient-based MultiObjective OptimizatioN Library in PyTorchcited by 10
- 2024Counterfactual Fairness by Combining Factual and Counterfactual Predictionscited by 8
- 2024Differentially Private Post-Processing for Fair Regressioncited by 5
- 2024A Unifying Post-Processing Framework for Multi-Objective Learn-to-Defer Problemscited by 5
- 2024Post-Fair Federated Learning: Achieving Group and Community Fairness in Federated Learning via Post-processingcited by 4
- 2024Inducing Group Fairness in Prompt-Based Language Model Decisionscited by 3
- 2025Fairness-Aware Grouping for Continuous Sensitive Variables: Application for Debiasing Face Analysis with respect to Skin Tonecited by 3
12 most cited of 49 All 49 (JSON)
- 2026Sensitive-Topic Leakage Through LLM Routing Metadata: Measurement and Mitigation7 Oct 2026
- 2026A Comprehensive View of Fairness through Distributional Stability29 Sep 2026
- 2026Interpretable and Fair Generalized Additive Neural Networks via Multi-objective Learning5 Sep 2026
- 2026Fair Classification with Efficient and Post-hoc Controllable Fairness-Accuracy Trade-off26 Jun 2026
- 2026Demystifying the Optimal Fair Classifier in Multi-Class Classification30 May 2026
- 2026A Model Ensemble-Based Post-Processing Framework for Fairness-Aware Prediction19 Mar 2026
- 2026Ethical Fairness in Ubiquitous Health Sensing without Known Attributes10 Mar 2026
- 2026Operationalizing Fairness: Post-Hoc Threshold Optimization Under Hard Resource Limits26 Feb 2026
- 2026Optimal Fair Aggregation of Crowdsourced Noisy Labels using Demographic Parity Constraints30 Jan 2026
- 2026Task-tailored Pre-processing: Fair Downstream Supervised Learning17 Jan 2026
- 2026Optimal Transport under Group Fairness Constraints12 Jan 2026
- 2025Metanetworks as Regulatory Operators: Learning to Edit for Requirement Compliance17 Dec 2025
12 newest of 49 All 49 (JSON)