Bolei Ma


2024

pdf bib
“My Answer is C”: First-Token Probabilities Do Not Match Text Answers in Instruction-Tuned Language Models
Xinpeng Wang | Bolei Ma | Chengzhi Hu | Leon Weber-Genzel | Paul Röttger | Frauke Kreuter | Dirk Hovy | Barbara Plank
Findings of the Association for Computational Linguistics ACL 2024

The open-ended nature of language generation makes the evaluation of autoregressive large language models (LLMs) challenging. One common evaluation approach uses multiple-choice questions to limit the response space. The model is then evaluated by ranking the candidate answers by the log probability of the first token prediction. However, first-tokens may not consistently reflect the final response output, due to model’s diverse response styles such as starting with “Sure” or refusing to answer. Consequently, first-token evaluation is not indicative of model behaviour when interacting with users. But by how much? We evaluate how aligned first-token evaluation is with the text output along several dimensions, namely final option choice, refusal rate, choice distribution and robustness under prompt perturbation. Our results show that the two approaches are severely misaligned on all dimensions, reaching mismatch rates over 60%. Models heavily fine-tuned on conversational or safety data are especially impacted. Crucially, models remain misaligned even when we increasingly constrain prompts, i.e., force them to start with an option letter or example template. Our findings i) underscore the importance of inspecting the text output as well and ii) caution against relying solely on first-token evaluation.

pdf bib
Order Effects in Annotation Tasks: Further Evidence of Annotation Sensitivity
Jacob Beck | Stephanie Eckman | Bolei Ma | Rob Chew | Frauke Kreuter
Proceedings of the 1st Workshop on Uncertainty-Aware NLP (UncertaiNLP 2024)

The data-centric revolution in AI has revealed the importance of high-quality training data for developing successful AI models. However, annotations are sensitive to annotator characteristics, training materials, and to the design and wording of the data collection instrument. This paper explores the impact of observation order on annotations. We find that annotators’ judgments change based on the order in which they see observations. We use ideas from social psychology to motivate hypotheses about why this order effect occurs. We believe that insights from social science can help AI researchers improve data and model quality.

pdf bib
Evaluating Lexical Aspect with Large Language Models
Bolei Ma
Proceedings of the Workshop on Cognitive Modeling and Computational Linguistics

In this study, we explore the proficiency of large language models (LLMs) in understanding two key lexical aspects: duration (durative/stative) and telicity (telic/atelic). Through experiments on datasets featuring sentences, verbs, and verb positions, we prompt the LLMs to identify aspectual features of verbs in sentences. Our findings reveal that certain LLMs, particularly those closed-source ones, are able to capture information on duration and telicity, albeit with some performance variations and weaker results compared to the baseline. By employing prompts at three levels (sentence-only, sentence with verb, and sentence with verb and its position), we demonstrate that integrating verb information generally enhances performance in aspectual feature recognition, though it introduces instability. We call for future research to look deeper into methods aimed at optimizing LLMs for aspectual feature comprehension.

pdf bib
Informing climate risk analysis using textual information - A research agenda
Andreas Dimmelmeier | Hendrik Doll | Malte Schierholz | Emily Kormanyos | Maurice Fehr | Bolei Ma | Jacob Beck | Alexander Fraser | Frauke Kreuter
Proceedings of the 1st Workshop on Natural Language Processing Meets Climate Change (ClimateNLP 2024)

We present a research agenda focused on efficiently extracting, assuring quality, and consolidating textual company sustainability information to address urgent climate change decision-making needs. Starting from the goal to create integrated FAIR (Findable, Accessible, Interoperable, Reusable) climate-related data, we identify research needs pertaining to the technical aspects of information extraction as well as to the design of the integrated sustainability datasets that we seek to compile. Regarding extraction, we leverage technological advancements, particularly in large language models (LLMs) and Retrieval-Augmented Generation (RAG) pipelines, to unlock the underutilized potential of unstructured textual information contained in corporate sustainability reports. In applying these techniques, we review key challenges, which include the retrieval and extraction of CO2 emission values from PDF documents, especially from unstructured tables and graphs therein, and the validation of automatically extracted data through comparisons with human-annotated values. We also review how existing use cases and practices in climate risk analytics relate to choices of what textual information should be extracted and how it could be linked to existing structured data.

pdf bib
ToPro: Token-Level Prompt Decomposition for Cross-Lingual Sequence Labeling Tasks
Bolei Ma | Ercong Nie | Shuzhou Yuan | Helmut Schmid | Michael Färber | Frauke Kreuter | Hinrich Schuetze
Proceedings of the 18th Conference of the European Chapter of the Association for Computational Linguistics (Volume 1: Long Papers)

Prompt-based methods have been successfully applied to multilingual pretrained language models for zero-shot cross-lingual understanding. However, most previous studies primarily focused on sentence-level classification tasks, and only a few considered token-level labeling tasks such as Named Entity Recognition (NER) and Part-of-Speech (POS) tagging. In this paper, we propose Token-Level Prompt Decomposition (ToPro), which facilitates the prompt-based method for token-level sequence labeling tasks. The ToPro method decomposes an input sentence into single tokens and applies one prompt template to each token. Our experiments on multilingual NER and POS tagging datasets demonstrate that ToPro-based fine-tuning outperforms Vanilla fine-tuning and Prompt-Tuning in zero-shot cross-lingual transfer, especially for languages that are typologically different from the source language English. Our method also attains state-of-the-art performance when employed with the mT5 model. Besides, our exploratory study in multilingual large language models shows that ToPro performs much better than the current in-context learning method. Overall, the performance improvements show that ToPro could potentially serve as a novel and simple benchmarking method for sequence labeling tasks.

2023

pdf bib
Is Prompt-Based Finetuning Always Better than Vanilla Finetuning? Insights from Cross-Lingual Language Understanding
Bolei Ma | Ercong Nie | Helmut Schmid | Hinrich Schuetze
Proceedings of the 19th Conference on Natural Language Processing (KONVENS 2023)

pdf bib
Annotation Sensitivity: Training Data Collection Methods Affect Model Performance
Christoph Kern | Stephanie Eckman | Jacob Beck | Rob Chew | Bolei Ma | Frauke Kreuter
Findings of the Association for Computational Linguistics: EMNLP 2023

When training data are collected from human annotators, the design of the annotation instrument, the instructions given to annotators, the characteristics of the annotators, and their interactions can impact training data. This study demonstrates that design choices made when creating an annotation instrument also impact the models trained on the resulting annotations. We introduce the term annotation sensitivity to refer to the impact of annotation data collection methods on the annotations themselves and on downstream model performance and predictions. We collect annotations of hate speech and offensive language in five experimental conditions of an annotation instrument, randomly assigning annotators to conditions. We then fine-tune BERT models on each of the five resulting datasets and evaluate model performance on a holdout portion of each condition. We find considerable differences between the conditions for 1) the share of hate speech/offensive language annotations, 2) model performance, 3) model predictions, and 4) model learning curves. Our results emphasize the crucial role played by the annotation instrument which has received little attention in the machine learning literature. We call for additional research into how and why the instrument impacts the annotations to inform the development of best practices in instrument design.

pdf bib
Baby’s CoThought: Leveraging Large Language Models for Enhanced Reasoning in Compact Models
Zheyu Zhang | Han Yang | Bolei Ma | David Rügamer | Ercong Nie
Proceedings of the BabyLM Challenge at the 27th Conference on Computational Natural Language Learning