Robust Representation Learning through Explicit Environment Modeling
Summary
This paper introduces a novel approach to robust representation learning for out-of-distribution (OOD) generalization, specifically addressing scenarios where environmental factors directly influence the target variable, a condition not typically handled by traditional causal invariant-representation methods. The authors propose explicitly modeling environmental variation and then marginalizing it out to learn representations that support robust prediction across unseen environments. They instantiate this through generalized neural random-intercept models, a class of predictors enabling such marginalization. Empirical evaluations on synthetic data, Colored MNIST, OGB-MolPCBA, and Camelyon-17 datasets demonstrate that these models consistently outperform invariant-learning methods, achieving lower environment-average risk and higher predictive accuracy, even in misspecified settings. The work also provides a theoretical decomposition of environment-average risk, clarifying when robust representations are preferable to invariant ones.
Key takeaway
For machine learning engineers developing models for multi-environment or OOD generalization, consider adopting generalized neural random-intercept models (NGMMs). Your current invariant-learning methods might be suboptimal if environmental factors directly influence the target. NGMMs offer superior average predictive performance by explicitly modeling and marginalizing environment-specific variation, leading to better-calibrated predictions and higher accuracy in unseen settings like medical imaging or molecular prediction tasks.
Key insights
Explicitly modeling and marginalizing environmental variation yields more robust OOD generalization than invariance-seeking methods.
Principles
- Environment can directly affect target.
- Robustness prioritizes average predictive performance.
- Invariance is not always optimal for prediction.
Method
Fit a neural generalized random-intercept model by minimizing empirical marginal risk, then marginalize environment-specific random intercepts to form predictions for unseen environments.
In practice
- Use NGMM for OOD generalization tasks.
- Consider random-intercept models for heterogeneous data.
- Evaluate performance on unseen environments.
Topics
- Robust Representation Learning
- Out-of-Distribution Generalization
- Explicit Environment Modeling
- Neural Random-Intercept Models
- Invariant Risk Minimization
Best for: AI Scientist, Machine Learning Engineer, Research Scientist
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Editorial summary, takeaway, and curation by AIssential. Original article published by stat.ML updates on arXiv.org.