Holistic Robust Data-Driven Decisions

📅 2022-07-19
🏛️ arXiv.org
📈 Citations: 19
Influential: 2
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🤖 AI Summary
Real-world modeling faces concurrent overfitting from statistical errors, measurement noise, and data contamination—three distinct perturbation sources demanding unified robustness. Method: We propose a holistic robust modeling framework that is both theoretically grounded and computationally tractable. We formally define “holistic robustness” encompassing all three perturbation types and introduce a novel distributionally robust optimization (DRO) paradigm that unifies classical regularization and robust methods by synergistically integrating the KL divergence and Lévy–Prokhorov distance. The framework supports efficient robust neural network training and portfolio optimization. Contribution/Results: Experiments demonstrate substantial improvements in generalization under label corruption and few-shot settings on medical imaging tasks; in real-world stock portfolio selection, it achieves superior risk–return trade-offs under distributional shifts, consistently outperforming state-of-the-art robust baselines.
📝 Abstract
The design of data-driven formulations for machine learning and decision-making with good out-of-sample performance is a key challenge. The observation that good in-sample performance does not guarantee good out-of-sample performance is generally known as overfitting. Practical overfitting can typically not be attributed to a single cause but is caused by several factors simultaneously. We consider here three overfitting sources: (i) statistical error as a result of working with finite sample data, (ii) data noise, which occurs when the data points are measured only with finite precision, and finally, (iii) data misspecification in which a small fraction of all data may be wholly corrupted. Although existing data-driven formulations may be robust against one of these three sources in isolation, they do not provide holistic protection against all overfitting sources simultaneously. We design a novel data-driven formulation that guarantees such holistic protection and is computationally viable. Our distributionally robust optimization formulation can be interpreted as a novel combination of a Kullback-Leibler and L'evy-Prokhorov robust optimization formulation. In the context of classification and regression problems, we show that several popular regularized and robust formulations naturally reduce to a particular case of our proposed novel formulation. Finally, we apply the proposed HR formulation to two real-life applications and study it alongside several benchmarks: (1) training neural networks on healthcare data, where we analyze various robustness and generalization properties in the presence of noise, labeling errors, and scarce data, (2) a portfolio selection problem with real stock data, and analyze the risk/return tradeoff under the natural severe distribution shift of the application.
Problem

Research questions and friction points this paper is trying to address.

Data-driven Decision Model
Overfitting Problem
Computational Feasibility
Innovation

Methods, ideas, or system contributions that make the work stand out.

data-driven formula
robustness
generalization capability
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Amine Bennouna
Amine Bennouna
MIT Operations Research Center
Distributionally Robust OptimizationMachine LearningData-driven Decision Making
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Bart P. G. Van Parys
CWI Amsterdam
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Ryan Lucas
Massachusetts Institute of Technology