@article{liu-etal-2024-lost,
title = "Lost in the Middle: How Language Models Use Long Contexts",
author = "Liu, Nelson F. and
Lin, Kevin and
Hewitt, John and
Paranjape, Ashwin and
Bevilacqua, Michele and
Petroni, Fabio and
Liang, Percy",
journal = "Transactions of the Association for Computational Linguistics",
volume = "12",
year = "2024",
address = "Cambridge, MA",
publisher = "MIT Press",
url = "https://aclanthology.org/2024.tacl-1.9/",
doi = "10.1162/tacl_a_00638",
pages = "157--173",
abstract = "While recent language models have the ability to take long contexts as input, relatively little is known about how well they use longer context. We analyze the performance of language models on two tasks that require identifying relevant information in their input contexts: multi-document question answering and key-value retrieval. We find that performance can degrade significantly when changing the position of relevant information, indicating that current language models do not robustly make use of information in long input contexts. In particular, we observe that performance is often highest when relevant information occurs at the beginning or end of the input context, and significantly degrades when models must access relevant information in the middle of long contexts, even for explicitly long-context models. Our analysis provides a better understanding of how language models use their input context and provides new evaluation protocols for future long-context language models."
}
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<abstract>While recent language models have the ability to take long contexts as input, relatively little is known about how well they use longer context. We analyze the performance of language models on two tasks that require identifying relevant information in their input contexts: multi-document question answering and key-value retrieval. We find that performance can degrade significantly when changing the position of relevant information, indicating that current language models do not robustly make use of information in long input contexts. In particular, we observe that performance is often highest when relevant information occurs at the beginning or end of the input context, and significantly degrades when models must access relevant information in the middle of long contexts, even for explicitly long-context models. Our analysis provides a better understanding of how language models use their input context and provides new evaluation protocols for future long-context language models.</abstract>
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%0 Journal Article
%T Lost in the Middle: How Language Models Use Long Contexts
%A Liu, Nelson F.
%A Lin, Kevin
%A Hewitt, John
%A Paranjape, Ashwin
%A Bevilacqua, Michele
%A Petroni, Fabio
%A Liang, Percy
%J Transactions of the Association for Computational Linguistics
%D 2024
%V 12
%I MIT Press
%C Cambridge, MA
%F liu-etal-2024-lost
%X While recent language models have the ability to take long contexts as input, relatively little is known about how well they use longer context. We analyze the performance of language models on two tasks that require identifying relevant information in their input contexts: multi-document question answering and key-value retrieval. We find that performance can degrade significantly when changing the position of relevant information, indicating that current language models do not robustly make use of information in long input contexts. In particular, we observe that performance is often highest when relevant information occurs at the beginning or end of the input context, and significantly degrades when models must access relevant information in the middle of long contexts, even for explicitly long-context models. Our analysis provides a better understanding of how language models use their input context and provides new evaluation protocols for future long-context language models.
%R 10.1162/tacl_a_00638
%U https://aclanthology.org/2024.tacl-1.9/
%U https://doi.org/10.1162/tacl_a_00638
%P 157-173
Markdown (Informal)
[Lost in the Middle: How Language Models Use Long Contexts](https://aclanthology.org/2024.tacl-1.9/) (Liu et al., TACL 2024)
ACL