Structured Language Generation Model: Loss Calibration and Formatted Decoding for Robust Structure Prediction and Knowledge Retrieval
Minho Lee, Junghyun Min, Yerang Kim, Woochul Lee, Yeonsoo Lee
TL;DR
<3-5 sentence high-level summary> The paper addresses the gap in structured prediction for Generative Pre-trained Language Models by diagnosing a misalignment between internal structural representations and the output space. It introduces the Structured Language Generation Model (SLGM), which couples reinforced input formatting, two targeted losses (Structure and Slot Loss) and format-aware decoding to constrain outputs to task-valid formats. Across 5 tasks and 13 datasets, SLGM improves structure prediction without extra parameters and remains competitive with much larger models when using sub-1B parameter sizes, also functioning as a zero-weight adapter in low-resource settings. The framework’s model- and data-agnostic design suggests broad applicability for structured prediction and knowledge retrieval in LLM-powered systems.
Abstract
Modern generative pre-trained language models excel at open-ended text generation, yet continue to underperform on structure-related tasks such as NER, relation extraction, and semantic role labeling, especially when compared to encoder-only models of similar sizes. While this gap has been attributed to limited structure knowledge, we hypothesize this is also due to the missing connection between the model's internal representations of linguistic structure and the output space used during supervised fine-tuning. We propose the Structured Language Generation Model (SLGM), a model- and task-agnostic framework that reformulates structured prediction as a classification problem through three components: (1) reinforced input formatting with structural cues, (2) loss design, and (3) format-aware decoding that constrains generation to task-valid outputs. Across 5 tasks and 13 datasets, SLGM substantially improves structure prediction without relying on dataset-specific engineering or additional model parameters, strengthening alignment between the model's internal structure representation and output. It outperforms baseline fine-tuning on models of the same size, achieves comparable performance to much larger models when used with <1B parameter models, and acts as a zero-weight adapter that reproduces the benefits of dataset-specific fine-tuning in low-resource settings.
