Know When To Stop: A Study of Semantic Drift in Text Generation

Fuente: arXiv
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Autori principali: Spataru, Ava, Hambro, Eric, Voita, Elena, Cancedda, Nicola
Natura: Preprint
Pubblicazione: 2024
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author Spataru, Ava
Hambro, Eric
Voita, Elena
Cancedda, Nicola
author_facet Spataru, Ava
Hambro, Eric
Voita, Elena
Cancedda, Nicola
contents In this work, we explicitly show that modern LLMs tend to generate correct facts first, then "drift away" and generate incorrect facts later: this was occasionally observed but never properly measured. We develop a semantic drift score that measures the degree of separation between correct and incorrect facts in generated texts and confirm our hypothesis when generating Wikipedia-style biographies. This correct-then-incorrect generation pattern suggests that factual accuracy can be improved by knowing when to stop generation. Therefore, we explore the trade-off between information quantity and factual accuracy for several early stopping methods and manage to improve factuality by a large margin. We further show that reranking with semantic similarity can further improve these results, both compared to the baseline and when combined with early stopping. Finally, we try calling external API to bring the model back to the right generation path, but do not get positive results. Overall, our methods generalize and can be applied to any long-form text generation to produce more reliable information, by balancing trade-offs between factual accuracy, information quantity and computational cost.
format Preprint
id arxiv_https___arxiv_org_abs_2404_05411
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Know When To Stop: A Study of Semantic Drift in Text Generation
Spataru, Ava
Hambro, Eric
Voita, Elena
Cancedda, Nicola
Computation and Language
In this work, we explicitly show that modern LLMs tend to generate correct facts first, then "drift away" and generate incorrect facts later: this was occasionally observed but never properly measured. We develop a semantic drift score that measures the degree of separation between correct and incorrect facts in generated texts and confirm our hypothesis when generating Wikipedia-style biographies. This correct-then-incorrect generation pattern suggests that factual accuracy can be improved by knowing when to stop generation. Therefore, we explore the trade-off between information quantity and factual accuracy for several early stopping methods and manage to improve factuality by a large margin. We further show that reranking with semantic similarity can further improve these results, both compared to the baseline and when combined with early stopping. Finally, we try calling external API to bring the model back to the right generation path, but do not get positive results. Overall, our methods generalize and can be applied to any long-form text generation to produce more reliable information, by balancing trade-offs between factual accuracy, information quantity and computational cost.
title Know When To Stop: A Study of Semantic Drift in Text Generation
topic Computation and Language
url https://arxiv.org/abs/2404.05411