Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Understanding Why Generalized Reweighting Does Not Improve Over ERM   Empirical risk minimization (ERM) is known in practice to be non-robust to
distributional shift where the training and the test distributions are
different. A suite of approaches, such as importance weighting, and variants of
distributionally robust optimization (DRO), have been proposed to solve this
problem. But a line of recent work has empirically shown that these approaches
do not significantly improve over ERM in real applications with distribution
shift. The goal of this work is to obtain a comprehensive theoretical
understanding of this intriguing phenomenon. We first posit the class of
Generalized Reweighting (GRW) algorithms, as a broad category of approaches
that iteratively update model parameters based on iterative reweighting of the
training samples. We show that when overparameterized models are trained under
GRW, the resulting models are close to that obtained by ERM. We also show that
adding small regularization which does not greatly affect the empirical
training accuracy does not help. Together, our results show that a broad
category of what we term GRW approaches are not able to achieve
distributionally robust generalization. Our work thus has the following
sobering takeaway: to make progress towards distributionally robust
generalization, we either have to develop non-GRW approaches, or perhaps devise
novel classification/regression loss functions that are adapted to the class of
GRW approaches.

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The categories of this paper are: supr-con
14
The categories of this paper are: math-ph
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The categories of this paper are: comp-gas
9
The categories of this paper are: nlin
36
The categories of this paper are: cmp-lg
34
The categories of this paper are: chem-ph
0
The categories of this paper are: hep-ph
8
The categories of this paper are: hep-ex
33
The categories of this paper are: plasm-ph
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The categories of this paper are: q-alg
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The categories of this paper are: mtrl-th
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The categories of this paper are: cond-mat
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The categories of this paper are: acc-phys
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The categories of this paper are: q-bio
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The categories of this paper are: solv-int
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The categories of this paper are: astro-ph