Span annotation - annotating specific text features at the span level - can be used to evaluate texts where single-score metrics fail to provide actionable feedback. Until recently, span annotation was done by human annotators or fine-tuned models. In this paper, we study whether large language models (LLMs) can serve as an alternative to human annotators. We compare the abilities of LLMs to skilled human annotators on three span annotation tasks: evaluating data-to-text generation, identifying translation errors, and detecting propaganda techniques. We show that overall, LLMs have only moderate inter-annotator agreement (IAA) with human annotators. However, we demonstrate that LLMs make errors at a similar rate as skilled crowdworkers. LLMs also produce annotations at a fraction of the cost per output annotation. We release the dataset of over 40k model and human span annotations for further research.

Large language models show strong capabilities in natural language generation (NLG) and have been applied to translate complex structured data into human-readable insights. While these models excel at surface-level fluency, they remain unreliable as they produce factually inaccurate outputs and struggle with consistent logical inference beyond surface-level patterns. Moreover, they often lack a clear sense of relevance and produce shallow or uninformative insights.This proposal argues that a key source of these limitations is task underspecification, which requires models to make implicit assumptions about missing context.We investigate how such underspecification leads to unintentional assumptions and how these affect faithfulness and evaluation.We examine how models can identify missing premises and surface multiple plausible interpretations to make evaluation more rigorous. We also explore how to improve reasoning to enable deeper inferences, focusing on code generation and qualitative reasoning. Finally, we will evaluate how the underlying assumptions and depth of inference influence the perceived interestingness of the insights. By shifting focus from surface-level generation to assumption-aware deeper inferences, this work aims to improve reliability, interpretability, and user controlability in NLG.

Table-to-text generation (insight generation from tables) is a challenging task that requires precision in analyzing the data. In addition, the evaluation of existing benchmarks is affected by contamination of Large Language Model (LLM) training data as well as domain imbalance. We introduce FreshTab, an on-the-fly table-to-text benchmark generation from Wikipedia, to combat the LLM data contamination problem and enable domain-sensitive evaluation. While non-English table-to-text datasets are limited, FreshTab collects datasets in different languages on demand (we experiment with German, Russian and French in addition to English). We find that insights generated by LLMs from recent tables collected by our method appear clearly worse by automatic metrics, but this does not translate into LLM and human evaluations. Domain effects are visible in all evaluations, showing that a domain-balanced benchmark is more challenging.

We describe a reproduction of a human annotation experiment that was performed to evaluate the effectiveness of text style transfer systems (Reif et al., 2021). Despite our efforts to closely imitate the conditions of the original study, the results obtained differ significantly from those in the original study. We performed a statistical analysis of the results obtained, discussed the sources of these discrepancies in the study design, and quantified reproducibility. The reproduction followed the common approach to reproduction adopted by the ReproHum project.