SynEL: A synthetic benchmark for entity linking

Large language models (LLMs) offer significant potential for constructing commonsense knowledge graphs from text, demonstrating adaptability across diverse domains. However, their effectiveness varies significantly with domain-specific language, highlighting a critical need for specialized benchmarks to assess and optimize knowledge graph construction sub-tasks like named entity recognition, relation extraction, and entity linking. Currently, domain-specific benchmarks are scarce. To address this gap, we introduce SynEL, a novel benchmark developed for evaluating text-based knowledge extraction methods, validated using customer support dialogues. We present a comprehensive methodology for benchmark construction, propose two distinct approaches for generating synthetic datasets, and evaluate accumulated hallucinations. Our experiments reveal that existing LLMs experience a significant performance drop, with micro-F1 scores decreasing by up to 25 absolute points when extracting low-resource entities compared to high-resource entities from sources like Wikipedia. Furthermore, by incorporating synthetic datasets into the training process, we achieved an improvement in micro-F1 scores of up to 10 absolute points. We publicly release our benchmark and generation code to demonstrate its utility for fine-tuning and evaluating LLMs.