OTTER: Effortless Label Distribution Adaptation of Zero-shot Models

Fuente: arXiv
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Main Authors: Shin, Changho, Zhao, Jitian, Cromp, Sonia, Vishwakarma, Harit, Sala, Frederic
Format: Preprint
Published: 2024
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author Shin, Changho
Zhao, Jitian
Cromp, Sonia
Vishwakarma, Harit
Sala, Frederic
author_facet Shin, Changho
Zhao, Jitian
Cromp, Sonia
Vishwakarma, Harit
Sala, Frederic
contents Popular zero-shot models suffer due to artifacts inherited from pretraining. One particularly detrimental issue, caused by unbalanced web-scale pretraining data, is mismatched label distribution. Existing approaches that seek to repair the label distribution are not suitable in zero-shot settings, as they have mismatching requirements, such as needing access to labeled downstream task data or knowledge of the true label balance in the pretraining distribution. We sidestep these challenges and introduce a simple and lightweight approach to adjust pretrained model predictions via optimal transport. Our technique requires only an estimate of the label distribution of a downstream task. Theoretically, we characterize the improvement produced by our procedure under certain mild conditions and provide bounds on the error caused by misspecification. Empirically, we validate our method in a wide array of zero-shot image and text classification tasks, improving accuracy by 4.8% and 15.9% on average, and beating baselines like prior matching -- often by significant margins -- in 17 out of 21 datasets.
format Preprint
id arxiv_https___arxiv_org_abs_2404_08461
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle OTTER: Effortless Label Distribution Adaptation of Zero-shot Models
Shin, Changho
Zhao, Jitian
Cromp, Sonia
Vishwakarma, Harit
Sala, Frederic
Machine Learning
Artificial Intelligence
Popular zero-shot models suffer due to artifacts inherited from pretraining. One particularly detrimental issue, caused by unbalanced web-scale pretraining data, is mismatched label distribution. Existing approaches that seek to repair the label distribution are not suitable in zero-shot settings, as they have mismatching requirements, such as needing access to labeled downstream task data or knowledge of the true label balance in the pretraining distribution. We sidestep these challenges and introduce a simple and lightweight approach to adjust pretrained model predictions via optimal transport. Our technique requires only an estimate of the label distribution of a downstream task. Theoretically, we characterize the improvement produced by our procedure under certain mild conditions and provide bounds on the error caused by misspecification. Empirically, we validate our method in a wide array of zero-shot image and text classification tasks, improving accuracy by 4.8% and 15.9% on average, and beating baselines like prior matching -- often by significant margins -- in 17 out of 21 datasets.
title OTTER: Effortless Label Distribution Adaptation of Zero-shot Models
topic Machine Learning
Artificial Intelligence
url https://arxiv.org/abs/2404.08461